MIT LIBRARIES MM- 3 9080 03317 5834 Massachusetts Institute of Technology Department of Economics Working Paper Series Fire Sales in a Model of Complexity Ricardo J. Caballero Alp Simek Working Paper 09-28 October 28, 2009 RoomE52-251 50 Memorial Drive Cambridge, This MA 02142 paper can be downloaded without charge from the Social Science Research Network Paper Collection at httsp://ssrn.com/abstract= 1 496592 o : Model Fire Sales in a Ricardo J. of Complexity Caballero and Alp Simsek* October 2009 28, Abstract Financial assets provide return and liquidity services to their holders. However, during severe financial crises many asset prices plummet, destroying their provision function at the worst possible time. In this paper fire sales follows and market breakdowns, and of the we present a model financial amplification from them. The distinctive feature of our model is liquidity of mechanism that the central role played by endogenous complexity: As asset prices implode, more "banks" within the financial network become distressed, which increases each (non-distressed) bank's likelihood of being hit by an indirect shock. As this happens, banks face an increasingly complex environment since they need to understand more and more interlinkages in making their financial decisions. uncertainty, which reluctant to buy makes crisis ensues. relatively healthy banks, since they control or understand. This complexity brings about confusion and The now fear becoming embroiled liquidity of the The model exhibits and hence potential in asset buyers, a cascade they do not market quickly vanishes and a financial a powerful "complexity-externality." As a potential asset buyer chooses to pull back, the size of the cascade grows, which increases the degree of complexity of the environment. This rise in perceived complexity induces other healthy banks to pull back, which exacerbates the JEL Codes: Keywords: crises, E0, Gl, D8, fire sale and the cascade. E5 Fire sales, complexity, financial network, cascades, markets freeze, information cost, financial panic, credit crunch, pecuniary externality. "MIT and XBER, and MIT, respectively. Contact information: caball@mit.edu We thank David Laibson, Frederic Malherbe. Juan Ocampo and MIT for their comments, and the NSF for financial support. First and alpstein@mit.edu. at Harvard and seminar participants draft.: July 28. 2009. Digitized by the Internet Archive in 2011 with funding from Boston Library Consortium Member Libraries http://www.archive.org/details/firesalesinmodelOOcaba Introduction 1 Financial assets provide return and liquidity services to their holders. severe financial crises many asset prices plummet, destroying function at the worst possible time. These mechanism observed However, during their liquidity provision are at the core of the amplification fire sales Large amounts of distressed asset sales in severe financial crises: depress asset prices, which exacerbates financial distress, leading to further asset sales, and the downward spiral goes on. There are many instances of these dramatic recent financial history. Bernanke floor TARP and the chaos they trigger in As explained by Treasury Secretary Paulson and Fed Chairman to Congress in goal of the fire sales an emergency meeting soon after Lehman's collapse, the main during the subprime on the price of the assets held by crisis as initially proposed was, precisely, to put a financial firms in order to contain the sharp contrac- tionary feedback loop triggered by the confusion and panic caused by Lehman's demise. And a few years back, after the in his congressional LTCM intervention, testimony of October 1, then Fed Chairman Greenspan wrote 1998: "Quickly unwinding a complicated portfolio that contains exposure to manner of risks, such as that of to conducting a fire sale. flect The LTCM, in such market conditions amounts prices received in a time of stress longer-run potential, adding to the losses incurred be sufficiently intense and widespread that elevates uncertainty enough all it a do not fire sale seriously distorts markets re- may and to impair the overall functioning of the economy. Sophisticated economic systems cannot thrive in such an atmosphere." In this paper we propose a model of fire sales that builds on the idea that complexity, a feature strongly disliked by investors during downturns for the uncertainty rises endogenously during crises: As asset prices implode, (banks, for short) within the financial network may go more it generates, financial institutions under, which increases each bank's likelihood of being hit by an indirect shock from counterparty risk. This means that banks face an increasingly complex environment since they need to understand more and more interlinkages in making their financial decisions. Thus, perceived uncertainty rises with complexity and makes relatively healthy banks reluctant to buy since they now fear becoming embroiled in the cascade themselves, rule out this option in the time available. and a financial crisis ensues. and no reasonable amount of research can The liquidity of the market quickly vanishes In Caballero and Simsek (2009) we show the basic interaction between the size of the equilibrium cascade in a financial network and the degree of complexity of the portfolio problem facing banks. In that model banks have bilateral linkages in order to insure each The whole other against local liquidity shocks. system financial a complex network is of linkages which functions smoothly in the environments for which though no bank knows with certainty (that is, all the many possible connections within the network each bank knows the identities of the other banks but not their exposures). However, these linkages financial distress arises may also be the source of contagion when an unexpected event of somewhere During normal times, banks only need in the network. to understand the financial health of their neighbors, contrast, designed, even it is when a significant problem which they can learn at low cost. In network and the possibility of arises in parts of the cascades arises, the number of nodes to be audited by each bank rises since that the shock may uncertainty and they react to is it means that banks now Our the starting point of this paper. focus here is fire sales on secondary that arise in In particular, this paper introduces a secondary market in which banks these markets. can face significant by retrenching into a liquidity-conservation mode. markets and on the feedback between that environment and the in distress possible spread to the bank's counterparties. Eventually, the problem becomes too complex for them to fully figure out, which This structure it is sell their legacy assets to meet the surprise liquidity shock. The natural buyers of the legacy assets are other banks in the financial network, which receive an indirect hit. When the surprise shock is small, cascades are short can inspect their neighbors to rule out an indirect may also and buyers In this case, buyers purchase hit. the distressed banks' legacy assets at their "fair" prices (which reflect the fundamental value of the assets). In contrast, when the surprise shock is large, longer cascades possible which increases the complexity of the environment, an indirect hit. As a precautionary measure, they hoard trades in (now illiquid) legacy assets and assets A plummets shock. When and buyers cannot rule out liquidity even turn into and disengage from sellers. model is price of legacy the dependence of the cascade size on the price which leads to multiple equilibria for intermediate levels of the surprise legacy assets fetch a fair price in the secondary market, the banks in distress have access to more liquidity and thus the surprise shock bankrupt, leading to a relatively simple environment. the natural buyers rule out an indirect hit and demand is contained after fewer banks are When the environment fire-sale equilibrium is simple, legacy assets, which ensures that these assets trade at their fair prices. Set against this benign scenario a The to "fire-sale" levels. central aspect of our of legacy assets, may become where the price of legacy assets collapses to is the possibility of fire-sale levels, which . As the leads to a longer cascade and a greater level of complexity. become worried about an increases, natural buyers and/or sell their own and complexity hoard liquidity the)' legacy assets, which reinforces the collapse of asset prices. This amplification mechanism tial asset indirect hit level of is exacerbated by a complexity- externality. As a poten- buyer chooses to pull back, the size of the potential cascade grows and with it the degree of complexity of the environment (each bank needs to explore larger segments of the network to understand the risk it is exposed to) This . complexity induces rise in other healthy banks to pull back as a precautionary measure, which further exacerbates the fire sale and cascade. 1 Our framework has two liquidity externality that bank chooses it additional (and more standard) externalities: A network- stems from the interlinkages of the financial system; when a to raise external liquidity rather spreads the distress to other banks. And than to generate a it from fire-sale externality its own resources, that arises from the negative effects that a bank's distressed asset sales have on other banks' balance sheets. These two externalities are present in many network and liquidity models. They interact but are distinct from the complexity externality that we highlight, which stems from the feature that any decision that lengthens the potential cascade, increases the complexity of the environments that other banks need to consider. This paper sales, these is related to several strands of literature. happen because during (cf. Shleifer may if some choose not to arbitrage the run because they anticipate a better deal in the future. potential buyers are fire sale in Our model between these two views: Most potential buyers are unconstrained, and Pedersen fire (2008), but they are confused and hence More and Vishny (1992,1997)). Brunnermeier and Pedersen (2008) show that even not distressed or constrained, these model of financial crises the natural buyers of the assets (other banks) also experience financial distress recently, In the canonical fearful of going lies as in the short somewhere Brunnermeier about their normal arbitrage role (and in this sense they are distressed as in Shleifer and Vishny (1992)). is in It the complexity of the environment that sidelines potential buyers. There is an extensive literature that highlights the possibility of network failures and contagion in financial markets. An incomplete list includes Allen and Gale (2000), La- gunoff and Schreft (2000), Rochet and Tirole (1996), Freixas, Parigi and Rochet (2000), Leitner (2005), Eisenberg and Although we do not pursue this Noe (2001), avenue in and Cifuentes, Ferucci and Shin (2005) the paper, complexity probably plays a role the incompleteness needed for a pecuniary externality to arise. If in (see creating agents could sign contracts contingent on the events that follow a cascade, then the externality would be greatly reduced, However, as potential cascades lengthen, the number of contingencies that need to be written into contracts grow exponentially. Allen and Babus (2008) for a recent survey). These papers focus mainly on the mecha- nisms by which solvency and liquidity shocks In contrast, we take environment these phenomena plexity on banks' prudential actions. mechanism we emphasize lieve that That is, in this The contagion many even cascade through the financial network. as the reason for the rise in the complexity of the which banks make their decisions, and focus on the in of contagion. may paper literature financial institutions there if is a cascade, also It is is is com- worth pointing out that the complexity operational even for relatively small sometimes criticized would be caught up it is effect of this because it is amounts hard to be- in a cascade of bankruptcies. reasonable to expect that 2 would eventually be it contained (especially since banks take precautionary actions to fight the cascade). But as this paper illustrates, even partial cascades can have large aggregate effects, since they 3 greatly increase the complexity of the environment. Our paper is also related to the literature tainty in financial markets, as in Caballero on flight-to-quality and Knight ian uncer- and Krishnamurthy (2008), Routledge and Zin (2004), and Easley and O'Hara (2005); and to the related literature that investigates the effect of (2005), new events and innovations in financial markets, e.g. Liu, Pan, Brock and Manski (2008), and Simsek (2009). Our contribution literatures network is in endogenizing the rise in uncertainty itself. More broadly, this paper belongs to an extensive literature on flight-to- the financial system's ability to channel resources to the real for The organization economy and a decline (see, e.g., in Caballero a survey). of this paper network and the secondary market event) in the network. We is as follows. we describe the financial and we introduce a surprise shock (a rare benchmark case without complexity effects for assets, also discuss a In Section 2 (because banks can understand the network at no cost). results. relative to these from the behavior of the financial quality and financial crises that highlights the connection between panics and Kurlat (2008), and Wang Section 3 contains our main There, banks have only local knowledge about the financial network, and a sufficiently large surprise shock increases the complexity of the environment and leads to 2 See. e.g..Brunnermeier, Crockett, Goodhart, Persaud, an Shin (2009) which argue that the domino model of financial contagion is not useful for understanding financial contagion in a modern financial system since ".... It is only with implausibly large shocks that the simulations (of their model) generate any meaningful contagion. The reason is that the domino model paints a picture of passive financial institutions who stand by and do nothing as the sequence of defaults unfolds. In practice, however, they will take actions in reaction to unfolding events, and in anticipation of impending defaults...'' 3 The role of cascades in elevating party's risk complexity was also highlighted in Haldane's (2009) speech, who mechanism when he wrote that at times of stress "knowing your ultimate counterbecomes like solving a high-dimension Sudoku puzzle." nicely captures the . a breakdown in secondary markets. level of This section also highlights the dependence of the complexity on asset prices and demonstrates the possibility of multiple equilibria. In Section 4 we describe the three externalities in our setup and analyze their role in our The paper concludes with a main results. 2 Equilibrium without Complexity In this section, remarks section and several appendices. final we describe the basic environment and characterize the equilibrium a benchmark case in which financial institutions (banks, for short) have of the interlinkages between we show that the network if the banks in the financial network. all deep is (i.e., there markets do not break down and the financial network the size of financial cascades is, These number a large is is resilient to knowledge full benchmark In this of banks) secondary a perturbation. That contained and aggregate loan contraction is we obtain relatively benign results contrast with those for is limited. in the next section once we introduce complexity. The Environment 2.1 We consider an can be kept economy with three dates {0,1,2} in liquid reserves or reserves, a unit of the to firms, it then yields it 1 units at date The economy has n continuums is tP, composed which is in the next date. 2. units of legacy loans, z units of reserves set aside for Each bank has demand making new loans measure of demand deposits held by R units at date 2) driven depositors. pay 'The only reason for loaned is illiquid. continuums of these each continuum initial assets retail depositors as long as the economy Each . 1 refer to and b> as bank which consist of liabilities consist of units of z in this bank is solvent, 2. At date all demand 1 — y economy pay 1 a unit deposits held unit at date will (only) there be whether the bank uses the continuum is for all retail 1 depositors would rather of its flexible reserves has just legacy loans and the (equilibrium) price for these loans trade-off in this a unit the depositor arrives early (resp. late). There are no liquidity depositors at date its • The bank's at date 0. Note that a bank that loans arrive at date 2. assets to I.e. if if deposits in one other bank, and y units of flexible by one other bank. The demand deposit contracts (resp. by {V } we of identical banks and, for simplicity, our unit of analysis. Instead, kept in liquid If These new loans are completely of banks denoted 4 which a single good (one dollar) can be loaned to production firms. good yields one unit R> in is r < is 1 enough a secondary market for (see below). its flexible The reserves to banks to take other banks' decisions as given. central make new loans and to purchase legacy loans in the secondary market, or whether we describe below). of this liquidity in response to a rare event (that The banks' cross demand b (P w.here p {l,..,n} : demand now, all network A make These all bank but we -* 6" (1) in the subsequent will shut slot model down is i (i.e., 2 + and 1, the bank 9 dollars of losses of might may 3 (to an outsider) 1. To prepare {HS, H, B}, which and Simsek (2009) for reserves y as liquidity choose its A = J H, slot 1 as a remain solvent in order to at date for date 1, For will , bank this 1. may bring the banks take one at date are restricted to a discrete choice set for a related model with unrestricted action and sell all of its its its flexible keep or withdraw to hoard its flexible legacy loans its reserves either to is more make new profitable). bank which to pay the retail depositors equilibrium for bank In Caballero b° y in the and to keep A = 3 1, if is it able to pay they arrive its early. at date 1 takes one of its this W}. it ends up paying are no liquidity driven retail q\ at date 2 can refuse assumption, the continuation two forms. Either the bank and Simsek (2009), we motivate the formation of the and Gale (2000). facilitating bilateral liquidity insurance, as in Allen in the depositors the contracted depositors at least With is, the bank chooses whether to takes), but instead Banks know that there its B, to keep buy legacy loans deposits on the forward neighbor bank, A\ 6 {A', to all depositors. depositors, thus a choose loans or to At date R) (despite the precautionary measures (01,132) — balance sheet and to be a potential buyer of loans. That Given the rare event, a bank may not be able to pay (1, may 1 to extreme measure, less reserves as liquidity balance sheet. Alternatively, the bank secondary market (whichever J n has slot over to other banks via the financial network and A — legacy loans on bank uses some has z units this ingredient until the next section. and Gale (2000), payment spill its flexible legacy loans on amount p W) the banks' uncertainty about the secondary market, keeping a completely liquid balance sheet. As a this fc in the As the most extreme precautionary measure, the bank may choose Aq — HS, all own bank i the financial linkages (cross-deposits) in the network. simplicity (see Caballero its (l) ) the banks learn that a rare event has happened and one bank, b3 of the following actions hoard bW b?w ->...;-» denotes that the bank in slot > into financial distress at date space). -* a permutation that assigns bank b p ^ to sZof is distressed. Similar to Allen needs to them 0, w^ -» central feature of the in (1), banks know At date become — arc deposits in the forward neighbor. financial {l,..,n} » The financial network. of — deposit holdings form a financial network denoted by: = (ww ) hoards some it financial is solvent, network pays for its role in 5i = 1, <fi q{ < 1, > = t/o 1) and the 0, and J actions (A ,A{) to maximize q\ until ations to depositors, that bank, thus once it at date 2; or the depositors draw their deposits at date all The bank chooses withdraw retail depositors is, until q[ — 1. Increasing satisfies its liquidity obligations, to late depositors (f2 Note that the banks make - it q[ it is insolvent, pays its liquidity oblig- 1. can meet beyond then bank 1 has no benefit for the tries to maximize the return their decisions while facing uncertainty about the network structure. For expositional simplicity we assume that banks are infi- nitely risk averse (rather than just risk averse) with respect to the financial network, i.e. they evaluate their decisions according to the worst possible network realization which they find plausible. Secondary Market for Legacy loans are traded price r, Legacy Loans in a centralized exchange that opens at date the banks that choose 3 bank) while the banks that choose spend up to y HS A = sell all AJ = B —y units for each are potential buyers of legacy loans There (their flexible reserves). of their legacy loans (1 Given the loan 0. is no demand or supply and may for legacy loans outside of the network. A legacy loan traded in the secondary market and originator, it yields returns R— < 5 R is at date 2. held by a bank different than We assume 6 > which simplifies the subsequent analysis, but the economic results generalize also to the case 5 that there is an upper bound on endogenous loan of legacy loans give up units at date 2, R If while r if 2. (1992). Note buyers Since secondary loans return = (R~5) R—5 /R. freely disposed of at the scrap value rf ire 6 (0,ry a7T ), so a lower bound on prices. < r Tj aiTl potential buyers = rj air , spend all of their flexible reserves y on legacy loans, they are indifferent between buying legacy loans and making In other words, even though banks get returns slightly lower than in the 6 no potential buyer would demand legacy loans at a price greater than Legacy and new loans can be is 0. prices. In particular, potential units at date r fajr rf ire = which they could also use to make new loans, thus flexible reserves each loan has an opportunity cost of its secondary market, they are the natural buyers of these loans R new loans. from legacy loans purchased and Vishny in the sense of Shleifer 1 Banks - - Liabilities: 1 — demand z - a legacy loans. forward - A\ -• A': - A\ = 11': Keep deposits in forward neighbor. Withdraw deposits in forward ireaghbor. demaud deposits held by backward neighbor batik. - deposits in iH'itfhlxir 1 Banks choose an action A[ e {AMI'): Dare 2 puyment to retail depo -itors of measure due: 11 units total. a flexible reserves, - Date Balance Sheets Initial Assets: bank. .: Retail depositors dei.ri.aud Date and only if Banks learn li.it bank b becomes distressed and Iihh to make a liquidity payment of at date if t t licit deposits bank cannot promise lie fii > .1. t 1. Date 2 Banks choose an action € \ IIS, II. IS}: = IIS: Hoard liquid reserves arid sell legacy loans. •= //: Hoard liquid reserves, keep legacy loans ,4(| = 11: Use reserves to buy legacy loans or to make new loans .1;', - A(, .'1,'', Legacy loans are traded in a centralized exchange at price V. Figure 1: Thus, the market clearing condition Banks pay to late depositors. <fj Timeline of events. can be written as for legacy loans > ;i-y)X>{^ = tfS}-^l{^ = B] = if < The term on the first maximum term denotes the for each r £ hand left [rfire , rfair], potential demand. If enough legacy loans to the [rf^e, rfair], r £ [rfire, value rfire rf a j r ], then r the left then legacy loans trade at their and £ clear the market. is If selling left is hand fair if r flTe (r fire, r aiT ) r = (2) r fair left side of Eq. (2) if negative , loans, and they buy just some side of Eq. (2) is hand positive for each side excess supply of loans and the price (note that this happens only is value rf air potential buyers new hand the equilibrium price. If the then there £ r = side denotes the total supply of loans while the second are indifferent between buying legacy loans r r if is is for given by the scrap there are no potential buyers). We refer to this situation as a breakdown in the legacy loan market. Equilibrium Figure 1 recaps the timeline of events in this economy. Definition {AJ (p) , A\ 1. An (p) } J equilibrium {q\(p) ,qi (p) }J is a collection and a price Jb(p) We of can now define equilibrium: bank level r £ and actions [r fire , r /a7> ] payments for legacy loans such W given the realization of the financial network b (p) and the rare event, each bank that, chooses its actions according to the worst case financial network that the legacy loan and only early if We market if q\ (p) < Eq. (cf. (2) retail depositors tP , finds plausible, withdraw deposits 1. bank bJ=p ^K Note there exists a unique k 6 {0, network b that, for each financial .., j — n = which we define as the distance of bank p b3 the payoff relevant information for a bank ... n} denote the and (p) for each 1} such that - (i k) , from the distressed bank.' The distance k V and will play a key role in the analysis. is 8 The Benchmark without Complexity 2.2 We and the J, next turn to the characterization of this equilibrium. Let T € {1, slot of the distressed bank clears it We characterize the equilibrium in two steps: and payoffs for a given price start by describing the banks' actions and then solve level of legacy loans, r; for the equilibrium price using the legacy loan market clearing condition (2). Suppose the loan prices are fixed at some r £ [rfi re ,Tf a ir] and consider the banks' Consider a distressed bank that needs to optimal actions and payments in this setting. obtain liquidity at date the original distressed bank b p ^). This bank could try to 1 (e.g. obtain the required liquidity either by withdrawing choosing A\ A 3 = W) £ {H. HS}). It cross deposits at date its and/or by taking a precautionary action at date (i.e. 1 by by choosing (i.e. can be checked that the bank always weakly prefers ex-post liquidity withdrawal to the ex-ante precautionary actions, thus we fix banks' liquidity pecking order as follows: Assumption (LPO). The liquidity pecking order is such that a at least z units of liquidity at date 1 first chooses A\ — W, and bank that then (if will there is need need) resorts to ex-ante precautionary measures. Under assumption (LPO) and the parametric condition bank 6 p(l) , which has to make a liquidity payment of from the forward neighbor bank liquidity, 'We 8 use which also withdraws modulo n arithmetic b p(l+l its ^ . > 6 6 at date This puts bank b p ^ +l z, 1, the original distressed withdraws 1 index i, e.g. T — k = —1 deposits also in need of z units of deposits on the forward neighbor bank. for the slot its ' represents the slot As n— in Allen 1. Note that the definition of equilibrium has built in a conservative feature which characterizes financial markets in distress: Banks make their precautionary decisions based on the worst outcome they find plausible. This feature plays no role in the benchmark since banks know the actual financial network. and Gale (2000), are withdrawn, this triggers further A\ i.e. = W withdrawals until, in equilibrium, all cross bank for all j. In particular, a the original distressed bank b p ^) withdrawals. Anticipating that tries, will it in deposits need of liquidity (including but cannot, obtain any net liquidity through cross not be able to obtain additional liquidity at date 1, the distressed banks try to obtain some liquidity by taking precautionary actions at date 0. To simplify the characterization of the banks' date y The hand left bank that sells its <K(l~y)R. + (l-y)r fair side of this condition legacy loans is not new, as it bank that keeps promise to make A = J it its depositors at least a net liquidity H. The 1. legacy loans on its 1 payment its hand right book unit at date (i.e. chooses A\ — H believes that and averts insolvency. it liquidation outcome. of losses the unit to If 1 less than even 3 € {H, B}) can always (3), a bank that expects its flexible it bank can sustain while remaining i.e. the action reserves y, then is greater than y, A = H. Hence, this chooses A = HS to improve its since this is the maximum level if it refer to y as the bank's buffer, We next conjecture that, A the bank's expected loss 1 = HS) depositors at date 2, and its that chooses is Aq side of this condition ensures that a cannot avoid insolvency and thus We ensures that a It 0. at date 1 first considers hoarding liquidity, then the bank expects to be insolvent at date bank 1 Under condition 2. the bank's expected loss at date If > that chooses the most precautionary action (i.e. be insolvent at date will (3) follows from 5 it does not have enough resources to promise at least thus we assume actions, J chooses J solvent. under appropriate parametric conditions (including condition K (r) £ {l,..,n — 2}, which depends on loan prices, such that banks with distance k < K (r) — are insolvent (there are K (r) such banks) while the banks with distance k > K (r) remain solvent. That the crisis will partially cascade through the network but will be contained after K (r) < n — 2 banks have failed. We refer to K (r) as the cascade size. (3)), there exists a threshold all 1 is, The than original distressed bank, b p{ \ its l - is insolvent as long as buffer y (and greater than z so that assumption its required payment (LPO) applies), i.e. if is greater and only if 6>max(y,z). Suppose this is the case so bank f^ is insolvent Id (4) Anticipating insolvency, this bank — HS, chooses Aq all retail depositors will arrive early at date {r) Ql _ ~ + r(l-y)-e + l + z y z and the bank will pay 1, <l Note that the to each depositor (where the inequality holds in view of condition (3)). bank it have y will + r (1 — Consider next the bank its 6 P '' -1 bank needs to pay 1 on its Hence, bank 6 p( ' ^ are greater than will also become buffer, z its ( 1 — pay p(l) insolvent p qx > j so , 1 it fr 6 P * !+1 ' and of 8, (which is unit for each unit of deposit). p( '~ 2) loses z (and only if make a payment from the distressed bank. To remain 1 deposits to bank deposits from the distressed bank 6 -1 will with distance ^ will 1, it forward neighbor bank its and thus solvent in our conjectured equilibrium on from will receive z units in cross-deposits solvent, this date y) units of liquidity at but it — P 1 ( 1 in cross-deposits. q J losses if) its < receives only q[ from cross-deposits which can be rewritten as y, qf <\-\. ] condition If this cascade size is fails, the only insolvent bank = 1. If this condition holds, then bank = HS, and it will pay its depositors ^ ,*-„ . j (with k this point > 1) is this bank's i. = + 6 p ( t_1 > and the anticipates insolvency rd-,)-^ (5) onwards, a pattern emerges. The payment by an insolvent bank b pi-'~ given by p{%— k) 9i and the original distressed bank K (r) and chooses Aq From is backward neighbor 6P ' = I r p( / (Si !_ ' A:+1 " is also insolvent if and only if q{ < 1 — -. Hence, the payments by insolvent banks converge to the fixed point of the function / and if y then there exists a unique K (r) > k) qf~ and g**-C*(r)-U> If (.), n — 2 is + r(l-y)>l-Z, 2 such that <l> greater than the solution, (6) ! _ V - for each k E {0. ... K (r) V__ K (r), to this equation, 11 i.e. if - 2} (7) n > K (r) + 2, (8) then, Eq. (7) shows that (in addition to the trigger-distressed with distance k 6 ..,K {1, (r) — bank 1} are insolvent since their losses b p ^) all banks fe^( t_fc ' from cross deposits are to improve their greater than their corresponding buffers. These banks choose Aq = p(l ~ h( r ^ is solvent, since it can meet its losses by liquidation outcome. In contrast, bank b = H. Since bank £^( l ~ A M) is solvent, hoarding liquidity, i.e. this bank chooses Aq HS - all 6 p( banks -/c ' ) {K with distance k £ (r) + 1, ... n — they do not 1} are also solvent since incur losses in cross-deposits. These banks are potential buyers of legacy loans, choose AQ — J conditions Note B. This (3), (4), (6) verifies , also that Eqs. our conjecture for a partial cascade of size and (8). (5) and imply that (7) loan price, the liquidation value of each bank is K (r) is decreasing in greater, thus the crisis i.e. K (r) they under with a higher r: contained after is a smaller number of insolvencies. For future reference, we strengthen condition (6) to + r fire (l-y)>l-^, y so that there exists a partial cascade for any r e \vj lTe rj a i T , (9) ] The next lemma summarizes . the above discussion. Lemma 1. Suppose information is that the loan prices are exogenously fixed and that conditions of size K(r), where bank k < distance k K (r) K (r) K (r) + > Figure 1 — (3), (4), (8) K (r) 1 is , and atr£ 2 displays illustrating that K (r) is [rfire, Then, there exists a partial cascade A =H AQ = B r. . the distressed The transition bank with The remaining banks with distance 3 r fair] for decreasing in A — HS. J J the equilibrium cascade size ogenously fixed at some r G assumption (LPO) holds, Banks with distance from and they choose and they choose network b(p), the financial ry ajr ], that , (9) are satisfied. averts insolvency by choosing are solvent [ry, re defined by Eq. (7). are insolvent know free so that banks K (r) when the loan prices are ex- a particular parameterization of the model, The negative dependence of the cascade size the price of loans will play an important role in the next section in which on we consider the equilibrium with endogenous complexity We rium next consider the legacy loan market clearing condition and solve for the equilib- level of prices in the free-information large, the To endogenous loan price benchmark. in the free-information see this, note that the insolvent banks (there are 12 We claim that benchmark K (r) of is if n is sufficiently = Tf air A J — HS given by r them) choose . K-(r) 05 15 1 25 2 45 4 35 3 5 Cascade size in the free-information benchmark. The plot cascade size K (r) when the loan prices are exogenously fixed at r £ [0, rf air Figure displays the 2: ] a given (for level of 9). and hence the aggregate supply of loans is given by ^~ K T )) chooses to hoard liquidity while the remain(r) (1 — y). The transition bank bp ^~ k J — B, i.e. ing solvent banks {b p (there are n — (r 1 of them) choose sell all of their existing loans, K ^ ^ the}' are potential (n Under 'fair ' K , buyers of loans. Suppose n - is level r < demand from rf mr , if the cascade is only partial and banks When there are sufficiently to absorb the supply r fair (10) ) assumption. The next 1. that much. flexible reserves to many banks, the the financial network, then These banks do not purchase loans from distressed demand from these solvent banks is . We refer to condition (10) as the deep secondary market proposition summarizes the above discussion and characterizes the symmetric equilibrium Proposition know know from the distressed banks, ensuring that the secondary loans are traded at their fair price rj air and [r fire , thus the loan market clearing condition (2) implies that hoard liquidity and are ready to use their b(p). G the potential buyers exceed the supply of loans there exist banks which will remain solvent and enough for all r • Intuitively, banks. A sufficiently large so that K (r) - 1) y > r (1 - y) K (r) this condition, the any price for , for the free-information Suppose information is benchmark. free so that banks Suppose assumption (LPO) holds, conditions the deep secondary market assumption (3), (10) holds. 13 know (4). Then: (8), the financial and (9) network are satisfied, r(8) = r, a ir 0.5 i- 0.6 0.7 0.9 0.8 1.2 1.1 1 1.3 1.4 1.5 6r 4 - 2 - — / ' oL 0.6 0.7 0.9 0.8 1 1.1 1.2 1.3 1.4 1.5 11 12 13 1.4 1.5 ~~\ Y(B) 11 >- 10.5 10 0.6 08 07 09 1 t Figure 3: Equilibrium in the free-information benchmark. The top, the middle, and the bottom panels respectively plot the loan prices, the cascade size, and the aggregate new level of (i) loans as a function of the losses in the originating bank. The unique equilibrium price (ii) given by r is For the continuation equilibrium with distance k < K{rf au — .) 1 = rj mT . All banks choose A\ (at date I): = are insolvent while the banks with distance k W . Banks > K(rj air ) are solvent. (Hi) For the ex-ante equilibrium the transition bank with distance banks with distance k (i.e. (iv) > K (rj K {rf air The insolvent banks choose (at date 0): ) ai r ) + chooses 1) choose For the loan market: The insolvent banks market, while the solvent banks with distance k buying legacy loans and making new loans. > A Q = H, A = B. J The aggregate all J other solvent banks J of their loans in the secondary sell all K (r/ a ,>) + are indifferent between 1 These banks spend a portion of their flexible reserves to buy the legacy loans sold by the insolvent banks the rest of their reserves. and A — HS level of new and they make new loans with made loans in this economy is given by: y= Discussion. ( n - K [rfair) - 1) V ~ Figure 3 displays the equilibrium K (r }air in the ) (1 - 11) y) r fc benchmark economy for particular parameterization of the model. The figure demonstrates that the loan prices are fixed at rf ai r , the cascade size is increasing in 6, and the aggregate 14 level of new loans is decreasing more Intuitively, as 9 increases, there are in 9. As the insolvency the spread of the insolvency. reserves as liquidity instead of decreases "smoothly" with we show making new These 9. losses to with small increases more banks hoard spreads, results offer a benchmark K There for the next section. y may and 3-' experience large changes in 9. Endogenous Complexity and Fire Sales 3 Let us repeat the steps of the previous section but now with only have local knowledge about the financial network Each bank observes its two forward neighbors but b is we assume this uncertainty takes a simple form: our key assumption: Banks (p). otherwise uncertain about remaining banks are allocated to the remaining financial slots (cf. Eq. > their distances and assign a In this context, when positive probability to the shock mark. But when the shock is large, is small, the all complex linkages 2 know distances k £ {3.4, — ..,n system behaves exactly as their about 3 are uncertain 1}. in the bench- banks need to understand distant (complex) linkages order to assess the amount of counterparty risk they are facing. figure out these how the (1)). In particular, Banks with distance k < distances from the distressed bank, and banks with distance k in their flexible which lowers y. Note, however, that loans, that once auditing becomes costly, both be contained, which increases Their inability to which overturns triggers a set of precautionary actions the relatively benign implications of the benchmark environment. As in the benchmark, the original distressed bank bp ^ withdraws its deposits from the forward neighbor bank, which triggers further withdrawals until, in equilibrium, cross deposits are withdrawn, it i.e. A\ = W cannot obtain any net liquidity at date condition (4), it also knows that Next consider a bank bank to choose action from its b> it for all j. Since the distressed 1, it tries with distance k > Aq £ {HS,H, B) is 0, the and note that a amount it it the bank chooses A J Formally, at date then this bank's paj'ment can be written as a function However, the bank chooses consequently about choice of action. x. That AQ Note is, J its it its precautionary will lose in cross- forward neighbor pays x deposits. 1, — HS. expects to receive in equilibrium and at date Under sufficient statistic for this measure, this bank only needs to know whether (and how much) if chooses Aq In other words, to decide on the level of forward neighbor. bank knows that to obtain liquidity at date 0. cannot avoid insolvency, thus all [q\ [-4q,.t] . <£> [^cb x ])- while facing uncertainty about the financial network, and 3 also that qi \A ,x] the bank's payment 15 is and q2 [Ag,x] are increasing in x for any increasing in the amount it receives from its forward neighbor regardless of the ex-ante precautionary measure the bank from its infinitely risk averse, is will it choose precautionary action as its forward neighbor the lowest possible payment To characterize the bank's optimal action We librium. further, say that the equilibrium allocation Thus, since takes. it if it will receive x. we define a useful notion of equi- distance based and monotonic is the if banks' equilibrium payments can be written as an increasing function of their distance That from the distressed bank. Qi,Q 2 {0, ...n -1}-*R p {i b and (p) We k. payment functions there exists weakly increasing such that - k) {i - k) (p)^2 (q1 for all is, = (p)) (Qi[k]y conjecture (and verify in Appendix A.l) that the equilibrium is distance based and monotonic. Under this conjecture, consider again V a bank with distance k the payment of the bank's forward neighbor can be written as x the bank's uncertainty about the forward neighbor's payment x its than own its distance k E {1-2}, then = receive x Q\ uncertain about it [k — its \k — 1 is k. the bank knows If chooses its from 1] distance, distances k E {3, ...,n Qi — uncertainty about the forward neighbor's distance k — minimal chooses Aq E {HS, H, 1}. i.e. if k > 3, then Moreover, since Qi for the distance k B} as A J if it = x Q\ Q\ [k is and note that — [k — 1] Then, 1], reduces to equal to one less On B} knowing the other hand, that the if i.e. if will it bank is it assigns a positive probability to all is an increasing function, the payment [.] Hence a bank 3. will receive = which £ {HS, H, forward neighbor. its 0, distance to the distressed bank, its optimal action 1, — > = Qi [2] from with distance k b> its > forward neighbor. 3 In words, the banks that are uncertain about their distances to the distressed bank choose their precautionary action as if they are closer to the distressed bank than they actually are. Formally, our next lemma establishes that action that the bank with distance k available (characterized in K (r) = so that the 3, Lemma 1). = If = H to avert insolvency, then all banks A\ = H even though ex-post they end up is even greater (i.e. if K (r) > banks with distance k > would choose if - A — with k 3 > 3 fold the information was freely > is given by 3 also take the precautionary action not needing liquidity. 4) so that the by taking the most precautionary action 16 choose the would take the precautionary action — HS, A Q — HS, J If the free-information bank with distance k — be insolvent and choose the most precautionary action Aq k 3 the free-information cascade size bank with distance Aq cascade size 3 all then all 3 would banks with which ensures that their insolvency (even though some of these banks would be solvent in the free-information economy). The proof of the following lemma is Lemma Consider the setup of free, so that banks know Lemma the equilibrium, b Let (p). K (r) of (characterized in is than costly rather denote the cascade size that would obtain Lemma Lemma that it Each bank IP with distance would choose in the free-information economy Each bank V with distance k £ 1). if 1). distance based and monotonic. is same action 2} chooses the 1, now information but 1, information was freely available (characterized in k £ {0, most only their two forward neighbors and they are otherwise uncertain about the financial network Then since provided by the above discussion. the intuition 2. Appendix A.l relegated to is {3, ... n — 1} chooses the same action that the bank with distance 3 would choose in the free-information economy. In particular, there are three cases to consider, depending on the cascade size: If K (r) < then the crisis in the free-information economy would not cascade to 2. bank with distance k £ {3. ... n — 3, 1} chooses to the free-information given by If A = J still = same as 3. which would choose K (r) > £ {3, ..,77 insolvent, i.e. — 1} chooses In particular, the cascade size is A — HS. J the cascade size free-information cascade size in the loan = 3) or A =H J A = J Thus each H. The equilibrium cascade K (r) i.e. to avert insolvency. = K (r). size is but the banks' actions then bank with distance 3 would be insolvent in the free-information 4, is K (r). market, while Thus, given by Note that the loan trade decisions K (r) 1. different. economy and would choose (if Lemma in the free-information economy, and payments are buyers each bank b3 with distance Thus, then the crisis in the free-information economy would cascade to and 3. b3 with distance k If B. K (r) = K (r). K (r) the J B, and the equilibrium actions and payments are identical economy described stop at bank with distance bank A = which would choose if all K (r) = of the they are potential > and they are all n. if K (r) < 2, > 3 depend on the these banks are potential they are either neutral in the loan market 3, sellers (if 3 banks with distance k In particular, K (r) A = HS banks choose K (r) loan trades on the free-information cascade size A" price) plays a key role in subsequent analysis, > (7') 4). This dependence of the banks' (which itself depends on the loan where we endogenize the loan prices and complete the characterization of the equilibrium. We next solve the equilibrium level of loan prices in the costly information setting and present our K (r) main results. There are three cases to consider depending on the cascade over the price range r £ \rj ire , rjfair] a 17 size Case K (r/ If (i). we rium, that jre < ) then we conjecture that there 2, and loans trade K (r) is J K (r) a decreasing function so that r$ aiT < Lemma r, To . K (rf ire verify this conjecture, recall that < ) € [r^ re 2 for all r the equilibrium price Case If (ii). which we r Lemma A = HS J K (rf mr ) (10), the unique equilibrium price Lemma in > 3, 2, 3 choose (if = r flTe To . we conjecture that there see this, note that 3 2 implies that K (r) > is all < is which there K (r/ azr ) < is there is Case Once . a breakdown in the loan K (r) banks with k > 3 choose either G for all r H A — 3 (if [rj lTe , rj air ], K (r) = 3), or words, these banks are either neutral in the legacy loan market 4). In note that the banks with distance k sellers in the legacy least 3 sellers rf aiT a unique symmetric equilibrium, or they are sellers, in particular, they are not potential buyers. Using and become = given by r proving our conjecture for this case. refer to as the fire-sale equilibrium, in market and < Lemma 2 once more, AJ = HS 2 are necessarily insolvent, so they choose loan market. Thus, the legacy loan market features at but no buyers. The market clearing condition (2) implies that r = r ire , i.e. a breakdown in the secondary loan market. (iii). equilibria: If K{rj air < ) Then, the analysis fair-price equilibrium. 3 < K{rj ire ), we loans, given by r (i) = ire ) > 3. To see this, first sup- all K (r) price of loans is given by r for case (ii) — rj ire , 2. — is a rj ire so that applies unchanged, 3 are either neutral in the loan prices collapse 'to r < banks with distance rj mT clears the market, verifying that there Then, the analysis banks with distance k > and loan fire-sale equilibrium. applies unchanged, in particular, and the price K (rf conjecture that there are two stable rj aiT so that the cascade size satisfies Next suppose that the the cascade size satisfies in particular, all is for case 3 are potential buyers sell their < 2 one fair-price equilibrium and one pose that the price of loans > > banks with k 2 implies that all Hence, determined, the remaining equilibrium allocations are uniquely is determined as described k rf a i r ]. , B, and as such, these banks are potential buyers of loans. Thus, under the deep sec- ondary market assumption thus = at their fair price r regardless of the endogenous price A = which loan markets endogenously refer to as the fair-price equilibrium, in clear a unique symmetric equilib- is market or they verifying that there is a fire-sale equilibrium. We summarize these Proposition 2. results in the following, and main, proposition. Consider the setup of Proposition 1 with the difference here being that banks only have local understanding of the network, so that banks know only their two forward neighbors and they are otherwise uncertain about the financial network h(p). 18 K (r) Let [r fi re , denote the cascade size in the free-information economy with price level r £ r a i r ] (characterized in Lemma loan market clearing condition (2) = price r r fair same size is the make new using their reserves to and r level of new loans Fire sale equilibrium.: If = r f ire K (rfi = re ) K {rfire) (u.2) If K{rf aiT < ) A = HS and sell their loans, > A" + l choose Aq = B and are indifferent between J 1) choose equal to the benchmark Eq. (11). K (rf air ) > then there 3, i.e. > 4, banks with distance k K = K (rf size is all. is a unique equilibrium, in which there In either sub-case, > an excess supply of loans is 3 choose A =H 3 These banks . iTe ). banks with distance k banks go under and the cascade size in this case is K= > A = HS. } 3 choose These n. new reserves are hoarded as liquidity and there are no all flexible 0. Multiple equilibria: If (ivi) K— i.e. loans or to buy legacy loans in the secondary market. is 3, all remain solvent and the cascade y= at their fair . (u.l) If loans, K < — a breakdown in the secondary loan market, is and loans trade as the free-information benchmark, while the solvent banks with distance k (ii) a unique equilibrium in which the satisfied with equality is The insolvent banks (with distance k The aggregate 2, there is . The cascade there < Fair-price equilibrium: If K{rj., re ) (i) 2. 1). K (r/ a jr ) < < 2 3 < K{rj ire ), there are two stable equilib- ria. In the fair-price equilibrium, loans trade at their fair price r size is K = K (rf a ir) < 2. the solvent banks are indifferent between purchasing loans in the secondary market, and the aggregate level of — rj mr the cascade , making new loans or new loans y is given by the benchmark Eq. (11). In the fire sale equilibrium, r K (rf dump ire ) — 3 ) or K = n K (rf (if ire ) = > rf ire 4), all their loans in the secondary market, Discussion. the cascade size , is given by either banks hoard liquidity and and there are no new loans, (if y K=3 K (r/,re ) (if > 4) —0. Figure 4 displays the equilibria with network uncertainty for a particular parameterization of the model. The top panel reproduces the cascade size free-information benchmark loan prices are fixed at r = as a function of the losses in the originating rf ire and 7' = r/ ,>. The remaining K (r) in bank 6, the when three panels display the equilibria with network uncertainty, illustrating the characterization in Proposition Note that there is a unique equilibrium for small and large levels of multiple equilibria for intermediate levels of 0. 19 6, 2. however, there are 5 ^ / 0.7 0.6 08 0.9 1.1 1 1 1.2 13 4 1.5 14 1.5 1 r(fl) Fair Price Equilibrium i- 5 Fire Sale Eq.uilibriuin | 0.6 0.7 08 09 1.1 1 .JL-: 1,2 1.3 40 ^ __--. «- *2) 20 06 0.7 8 0.9 1 15 1.1 1.2 11 1.2 T 1.3 , , 1.4 1.5 14 15 Y(B) 5 j .1. 06 07 08 09 1 1.3 8 Figure 4: Equilibria with network uncertainty. The top panel plots the cascade size K (r) in the free-information benchmark as a function of the losses in the originating bank 6, when loan prices are fixed at r £ {0,r/ ajr }. size The remaining three panels display the network uncertainty: They respectively plot the loan prices, the cascade and the aggregate level of new loans as a function of 0, for both the fair-price and equilibria with the fire-sale equilibria. L'O When K(rj ire 8 is sufficiently small so that benchmark features a short cascade even fair price ) < 2, when i.e. = for the price level r the free-information rf lTe there , is a unique equilibrium. This equilibrium features a low level of complexity thus the banks that are uncertain about their distance to the distressed bank can rule out an indirect hit. Consequently, these banks use their reserves to The aggregate new level of loans is make new loans and to demand assets. the same as in the free-information benchmark, and assets trade at their fair prices. In contrast, when 8 is sufficiently large so that size in the free-information is and discontinuous drop to zero. That is, when there new when 3, i.e. a unique fire-sale is loans the cascade makes a very large the losses (measuring the severity of the shock) are beyond a threshold, the cascade size becomes so large that banks are initial unable to whether they are connected to the distressed bank or not. All uncertain tell banks act as much more if they are closer to the distressed bank than they actually are, hoarding liquidity than benchmark, become in the free-information prices. in the free-information sellers to a severe and this leads to a collapse in asset This result provides a rationale for the collapse of asset prices in an environment which complexity suddenly (and endogenously) re benchmark and leading Moreover, these banks, some of which would be potential buyers credit crunch episode. K (rfi > ) sufficiently large, In this equilibrium, the aggregate level of equilibrium. in benchmark K{rf mr > ) rises. that the uncertain banks panic so 4) much Furthermore, it is possible (if that they take an extremely precautionary action to increase their liquidation outcome. However, ex-post, this action ensures that the uncertain banks become insolvent. When is high 8 (i.e. sale price is in an intermediate range, the cascade K (rj < K (r/,> air (i.e. endogenous ) e level of ) however 2), > 3). it size is manageable becomes unmanageable price of loans loans trade at the In this case, the interaction between asset prices fire- and the complexity generates multiple equilibria. In the fair-price equilibrium, loans trade at a higher price relatively small, if if which reduces the level of complexity. and the cascade With the lower size is level of complexity, the banks that are uncertain about their distance to the distressed bank become potential buyers of loans, which ensures that loans trade at the higher price and that the cascade is shorter. Set against this benign scenario is the price of loans collapses and there complexity. As the distances panic and Note also that, level of sell the possibility of a fire-sale equilibrium, in which is a longer cascade, which increases the level of complexity increases, banks that are uncertain about their their loans, which reinforces the collapse of loan whenever there are multiple 21 prices. equilibria, the fair-price equilibrium Pareto dominates the equilibrium for fire-sale sale equilibrium entails In the next section, insolvent. account two distinct we all banks and their depositors. social costs: fewer new loans Intuitively, the fire- and more banks become identify the negative externalities in our setup that for these social costs. Three Externalities 4 In this section, we discuss the various externalities present in our setup the role they play in our main results. which we call features three distinct externalities, the network-liquidity externality, the fire-sale externality and the complex- The ity externality. The second Our model and we highlight first of these emerges directly from the interlinkages externality stems from the interaction of loan prices between banks. and the endogenous determination of bank runs. These two externalities are relatively standard. Models of interconnected banks typically feature externalities akin to our network-liquidity externality (see, for example, Rotemberg (2009)), while models based on the Diamond and Dybvig (1983) setup typically lead to fire-sale externalities whenever prices affect the likelihood of bank runs (see, for example, Allen and Gale (2005)). The complexity externality and to our analysis, it is novel emerges from the interaction of loan prices and the complexity of the financial network. 4.1 Network-liquidity Externality In our setup, a distressed either withdraw serves (or a it can its bank can obtain sell its it can hoard its liquidity externality on it. bank scrambles (cf. A is scarce, forward neighbor bank also in distress, In particular, unable to meet this liquidity demand. withdraw deposits its if the bank decides to withdraw for liquidity distressed bank in and faces insolvency it can. ' its own Our The bank's liquid reserves, its if it our setup always (weakly) assumption (LBO)). 9 In Appendix A. 2, we study the polar opposite case, enforced by the government, in which a bank that needs liquidity hoards can It liquid re- legacy loans, as a last measure). Since aggregate liquidity cross deposits, the forward neighbor prefers to through two distinct sources: deposits on the forward neighbor bank, or bank that chooses the former option puts imposing a is liquidity and thus avoids inflicting first a liquidity externality whenever analysis shows that internalizing the liquidity externalities in this fashion preference for liquidity withdrawal is strict if the forward neighbor pays q% < R. In the more general model analyzed in Caballero and Simsek (2009). the bank always strictly prefers to withdraw deposits and thus always inflicts a liquidity externality. 22 leads to shorter cascades in aggregate (see Proposition 3 in the appendix). Intuitively, the scramble for liquidity a hot potato which the banks can either like is pass straight to their neighbors, or which they can cool before passing it on. When reaches a vulnerable bank, all banks pass it without cooling a bank which i.e. is This bank cannot pass the potato to bank. down it, a bit using their resources the hot potato eventually sufficiently close to the original distressed neighbor, which its already bankrupt. is Moreover, the resources of this bank alone are not sufficient to cool hence the bank burns it (i.e. down the potato cannot meet the liquidity demand and becomes insolvent), which lengthens the cascade. In contrast, when each bank cools down the potato before passing much it on, then the potato cold before is it reaches the vulnerable bank, leading to a shorter cascade. Fire Sale Externality 4.2 Consider a bank that decides to sell This action has a small positive loans, while loans. it effect has a small negative Absent further "net out," which is effects, some on the net budgets of the banks that buy legacy effect on the net budgets of the banks that sell legacy the welfare impacts of these budget changes would typically the content of the increases the likelihood of a loans, leading to a small decline in loan prices. first bank run in welfare theorem. However, a small decline also our setup, leading to a further decline in the welfare of these banks and their depositors. Consequently, the effects of price changes do not necessarily "net out," and loan prices feature a negative pecuniary externality. To formalize this point, let us consider the This setting shuts down benchmark economy analyzed the complexity externality (since the banks in Section 2.2. know the financial network) which we will analyze in the next subsection. K (r) Recall that the cascade size liquidation payment number after a smaller f £ [rfire, ffair] of each bank is for any e > decreasing in greater of insolvencies such that, is Eq. (cf. Eq. (cf. (7)). (5)), is, thus the crisis is contained In particular, there exists some we have K(f-e/2) = K(f + e/2) + That with a lower loan price, the r: l. the cascade size increases by one in response to an arbitrarily small decrease in loan prices. one more bank, The small inflicting backward neighbor, while price drop from f + a discrete negative it has a continuous 23 e/2 to f effect effect — e/2 leads to the insolvency of on the welfare of this bank and its on the welfare of other banks. Hence, for sufficiently small e, the net welfare effect of the price is negative, demonstrating the The fire sale externality. general intuition behind this externality change from r + e/2 to f — e/2 10 that a drop in asset prices lowers the is liquidation value of an insolvent bank, which increases the probability of a bank run in the counterparties of this bank. Complexity Externality 4.3 Consider next the model analyzed in Section 3 in which banks only have about the financial network. Similar to the above analysis bank that sells local information for the fire sale externality, a a loan has a small negative impact on loan prices, which in turn increases the length of the cascade. However, in this case, longer cascades also increase the comSince banks are averse to complexity (which plexity of the financial network. we model as infinite risk aversion with respect to the financial network), an increase in complexity leads to a welfare reduction for banks that are uncertain about the financial network. To formalize this point, consider the set of K (rj in Proposition 2, that, for any e > air < ) 2 < 3 < is, ire ). Then, there exists f £ [r fire, 1" fair] such we have K (f - e/2) That K (rf parameters that lead to multiple equilibria = 3 > K (f + e/2) = 2. small decline in loan prices makes the cascade size in the free-information benchmark exceed the critical threshold of Recall that the banks with distance 2. k G {3, ..,n— 1} mimic the bank with distance 3 in the free-information benchmark. Then, when the loans trade at price f + e/2, these banks know that they will not lose anything in cross deposits, thus they do not take any precaution and they pay out at least (<^ = 1,^ = R) to their depositors (and perhaps more, if they can acquire legacy loans at a discount). In contrast, {3, ..,n — when the loans trade at price f 1} are worried that they might suffer — e/2, the an indirect these banks are infinitely risk averse, their welfare is banks with distance k G hit from the cascade. Since greatly reduced. Moreover, these banks hoard liquidity to precaution against the worst case scenario, and they end up paying [q\ = 1, ql, < R) to their depositors. Hence, a small drop in prices inflicts a discrete 10 The discrete nature of the fire sale externality is due to our modeling assumptions, in particular, our assumption that the good equilibrium is selected whenever there are multiple equilibria for bank runs. However, the externality would also be present in other variants of the model, as long as the probability of a bank run is increasing in the date 1 losses (i.e. the severity of the liquidity shock) of the bank. 24 negative effect on all of the banks with distance k £ — {3, ...n and 1} their depositors, demonstrating the complexity externality. The complexity setup, as externality we have already seen complexity due to a reduction banks and may also lead to multiple Pareto-ranked equilibria in our in Proposition 2. In particular, in the price of assets not their depositors, but also induces these in panic mode reduces asset prices further, many banks to take extreme precautionary sales. The sale of assets by which leads to a vicious cycle culminating an increase in asset prices reduces the complexity which may mitigate the precautionary measures and turn more sellers into in the fire-sale equilibrium. In contrast, externality, in the level of only lowers the welfare of measures, which, in some instances, includes further asset banks an increase buyers, leading to a virtuous spiral towards the fair price equilibrium. Finally, note that the complexity externality the fire sale erature. is potentially externality analyzed in the previous subsection The reason is and highlighted in the lit- that the fire-sale externality affects banks that are on the verge of insolvency. In contrast, the complexity externality affects about the financial network, which, The much more potent than all banks that are uncertain in practice, includes virtually all financial institutions. greater scope of the complexity externality also leads to widespread (precautionary) actions, which has the potential to create aggregate effects, price changes, and multiple equilibria. Conclusion 5 In this paper we provide a model that illustrates how fire sales and complexity can ger a very powerful negative feedback loop within a financial network. sales lengthen the potential cascades, ponentially. This triggers confusion exacerbate the fire sale. and raise the among trig- More severe fire complexity of the environment ex- potential asset buyers, which pull back and In extreme scenarios these potential buyers can turn into sellers, leading to a complete collapse in secondary markets. In our model, the distressed institutions' motive for outcome in the worst case scenario of insolvency. This only to simplify the exposition. In reality, is fire sales is to improve their an extreme assumption the distressed institutions may multitude of reasons that do not imply anticipating insolvency. E.g. they to do so by regulatory requirements, or they may hope liquidity. main to avoid a sell made assets for a may be forced run by obtaining more These reasons can be incorporated into our framework while preserving our conclusions. 25 Having said what would happen of we the particular insolvency motive this, consider also raises the question the distressed institutions chose to gamble for resurrection by if not selling their assets, which would improve their outcome in good states at the cost of a greater bankruptcy mixed blessing Our model suggests that gambling risk. Gambling by potential buyers, that for the aggregate. know are far from the cascade but that do not downward On spiral of prices. would increase the cascade We ates size and supporting institutions that and the limit the fire sales it from counterparty apparent that our environment cre- Supporting secondary markets, insulating and risk, is stress testing (increasing transparency needed) systemically important financial institutions, are if be a and trigger the complexity mechanism. policy opportunities during crises. financial institutions would this, is, may the other hand, gambling by institutions near the cascade did not explore policy questions, but many for resurrection policies all practiced during the current financial crisis and supported by our framework. A Appendix Proofs Omitted in the A.l Proof of Case (i): Lemma K (r) an equilibrium, 2 < first To prove that the conjectured actions and payments constitute 2. it level Q\ [0] amount receives the full in the conjectured equilibrium). z that it from would pay its forward neighbor, which it is it equal to what it its date action as if it it will receive would receive optimally chooses the same action chooses +l bp ^ \ which is solvent Next consider a bank with distance k £ {1,2}. Under > Consider next a bank with distance k thus economy in the free-information forward neighbor, the conjectured equilibrium, this bank knows that Hence, = HS note that the original distressed bank optimally chooses Aq and pays out the same (since Main Text it 3. — Q\ [k — 1] in the free-information would choose when information This bank will receive Under the conjectured equilibrium, the cascade x x size is = is Qi K (r) uncertain about [2] < from 2, its thus from economy. is free. its distance, forward neighbor. we have Q x [2] Since the bank makes no losses in cross deposits (even in the worst case scenario of k it optimally chooses A = J its = — 1. 3), B, verifying the optimality of the conjectured action. Since the banks' actions are the same as the free-information are also identical to that case, which verifies (by 26 Lemma 1) economy, their payments that the equilibrium is distance based and monotonia Case K (r) (ii): = the banks with distance k £ {1. 2} optimally choose the same action and payments it chooses K (r) = Since its date action as > with distance k chooses it This bank 3. will receive if it x = uncertain about is Q\ [2] from under the conjectured equilibrium, we have Q\ 3, benchmark) level in the free-information thus make the same as in the free-information economy. Consider next a bank with distance k thus bank and Similar to the previous case, the original distressed 3. > some 3 expects (with H A — J lies in the interval (1 probability) to make — its forward neighbor. (which [2] y/z. distance, its 1). is equal to its Hence, the bank losses less than its buffer, to counter these losses, verifying the optimality of its conjectured action. These banks with distance k > free-information economy. amount (Qi with distance k > [k] > 1 it would pay pay potentially bank with distance k = than the less 3 pays the in the free-information case, while the same banks 4 end up paying Q where Q% In particular, the that [3] ,(5-2 [3]) 3 are solvent, but they x [k] follows = 1 and from Eq. Q-2 [k] (3). = y + (1 - y) R It G (1, R) , follows also that the equilibrium is distance based and monotonia Case (iii): A' (r) > 4. In this case, note that the banks' payments, given the conjectured actions, are the solutions to the following Q, [0] ft [k] = ^(l-0)r-^^[n-l] = V+SL^jQlVtzl, (12) +z 1 Note that, system of equations: by condition (3), tor k € {1, ..,* also verifies that the equilibrium allocation {Q\ is . [k] < The system 1 in Eq. (12) verify the optimality of banks' actions, first note that Eq. (12) implies the i^]}fc=o are l°wer than what they would be would be solvent and would pay 1 for all k, distance based and monotonia in the free-information the forward neighbor of the original distressed bank pays Q\ [n it 1} the solution to this system satisfies Qi verifying that the banks are indeed insolvent given their actions. To - — 1] < 1 payments economy, because in this case (while unit per deposit in the free-information economy). Consider a bank with distance k G {1-2}, and recall that this bank chooses 27 its date action knowing that bank would be insolvent 4, this Q\ — [k will receive it 1] is [k — it would be chooses it neighbor. date its K (r) Since from its > > action as if it economy. we optimally chooses This bank is uncertain about necessarily have 3 believes that go bankrupt. Consequently, it Qi [2] = x Q\ r < 1 — [2] A = HS. J its distance its forward from are even lower than [k]} k:i might experience it economy. Thus the it will receive > In the present case, and and since the payments {Qi 4, the free-information economy, bank with distance k > 3. K (r) forward neighbor. Since in the free-information {1, 2} is necessarily insolvent, Consider next a bank with distance k and thus 1] in the free-information even lower than what bank with distance k 6 Q\ y/z. In other words, the losses beyond buffer its chooses the most extreme precautionary action and A = HS J to improve their liquidation outcome, verifying the optimality of the conjectured action. Equilibrium without Liquidity Externalities A. 2 In the main text, the bank always considers deposit withdrawal as the liquidity (cf. first assumption (LBO)), thus imposing a liquidity externality on source of forward its neighbor bank. To clarify the role of liquidity externalities, in this appendix we analyze the equilibrium under a government policy that prevents banks from withdrawing cross deposits unless they have used To facilitate the analysis, it all of their liquid reserves. helps to consider a slightly greater action space for banks: (Al A\) e {H where A = H (y) and A{ 3 = W (z) (y) , HS, B} x denotes that the bank hoards y e , (0, y] denotes that the bank withdraws z 6 the forward neighbor bank. In other words, flexible reserves {W (z) K} and to main assumption of partially this withdraw (13) , units of (0, z] we allow the banks their cross deposits. its flexible units of reserves, deposits on its to partially hoard their Next, we introduce the appendix: the government enforces the reverse of the liquidity pecking order in assumption (LPO) so that banks do not impose a liquidity externality on their forward neighbors, whenever they can avoid doing Assumption (LPO-R). forward neighbor bank bank is Consider a bank that needs liquidity at date solvent. such that the bank first The government imposed considers hoarding J 28 1 and whose liquidity pecking order for this its flexible reserves, i.e. it A = H (y). The bank withdraws some of its cross deposits if Aq — H (y) is not sufficient to meet its liquidity demand. action only is so. considers the (chooses A\ = W (z)) Finally, we strengthen the right hand side of condition (3) to l own so that a bank's + z<(l-y)R, legacy loans are enough to promise backward neighbor bank) at least 1 unit at date Under these assumptions and when n an equilibrium in (14) which is 2. we conjecture sufficiently large, > banks with distance k all depositors (including the all 1 all (i.e. bank In the conjectured equilibrium, the original and W withdraws also for the liquidity its flexible and = (Af b 2, p(-^: in ' need of pecking order, bank reserves. < z If bp ^ H {z),Af +1) if z — y < y, W = z (z —y (with distance n ' - y)\ Otherwise = H(z),A > hoarding =A p its flexible j reserves, y and this bank chooses bank b p{T+2 ^ is with distance similar to payment purely by hoarding withdraws an even smaller amount from it in — = HS and A P 1) first resorts to In this case, consider liquidity 1, 2. units of liquidity. This bank's response its most Under the new assumption — z at of its liquid reserves chooses Aq z units of liquidity. +1 all is its bank its flexible forward neighbor. follows that a pattern emerges for the banks' cross withdrawal decisions. In partic- n > ular, let 1 denote the unique integer such that yn > and suppose n > chooses n. Then, for , — its need any H (z — (n z each j £ {1, (Af+J) = H (y) Af+j) = chooses [Aq keeps it hoards payments purely by hoarding then the bank meets and otherwise i.e. ® and 1 then this bank chooses [Aq y, liquidity its which needs to find reserves, It P ' I+1 \ does not withdraw any cross deposits. +1] n— 6 the bank meets is, it deposits on bank b which puts bank (z), that its pi-' +1 bp is banks except potentially the original distressed bank) are solvent. In other words, the cascade size stark contrast with the equilibria characterized in Propositions that there — W \)y) {z - > y(n- .., n — 1) 1}, the bank b p(,+j) with distance n jy)) while the bank , ,A P = A j . Since the cross deposits, the remaining banks with distance k liquidity, and these banks withdraw their deposits ,(T+ri) with distance n-n bank with distance n — n 6 if ^ —j {1, ...,n and only —n— if 1} do not their forward neighbors are insolvent. Going back sections, this to the original distressed bank obtains a units from cross deposits total of y (if it + z bank b p ^\ note that, unlike in the previous units of liquidity: y units from its buffer remains solvent). Hence, this bank 29 is insolvent if and z and only if 9>y + z, which bp ^ a stronger condition than is is W this condition and consider the backward neighbor bank insolvent = Suppose (4). (15) 6 satisfied so that is p (' _1 bank This bank chooses ). and receives some gf' 2 < z from the original distressed bank. Despite ~1 is solvent and it can promise incurring some losses, in view of condition (14), bank b p<Kl Ai (~) ^ its late depositors (including the backward neighbor bank) at least = ? it pays (<2i liquidity, it 1 1, q^' chooses to keep with distances k G {2, ..,n > ' —n— 1 Since the backward neighbor bank 6 • deposits in its {1, ..,n ) —n— bank Repeating 2} are solvent, and thus = B,A^ 1} choose (Aq ^~ l bp \ 1 K), == all unit at date 2, 1 p ('~ 2 i.e. does not need ) this reasoning, all banks banks with distances k G in particular, keeping their deposits in their forward neighbor banks. Note also that there distressed 6 P '^) bank is at most one the conjectured equilibrium (the original seller in while the banks with distance k G {2, ...n —h— buyers of loans. Hence, under the deep secondary market assumption 1} are potential the analogue (i.e. of condition (10) for this setup), in the unique equilibrium price is 2)y>l-y, = given by r regardless of whether the banks have local knowledge —n know r_/ air (16) Note . also that this analysis applies the financial network b (p) or whether they only they know only their two forward neighbors). (i.e. We summarize this result in the following proposition. Proposition Suppose the banks' action space 3. for the liquidity pecking order the government) know , is b (p) (LPO-R) (which In particular, the original distressed bank the banks with distance k is — rj aiT and — 1, .., is the cascade size insolvent while G {1,0, n is (LPO) imposed by Then, regardless of whether the banks or just their two forward neighbors, there equilibrium in which loan prices are given by r 1, extended to (13), assumption replaced by assumption conditions (15) and (16) hold. the financial network At date is n—n— all a symmetric is equal to other banks are solvent. 1} withdraw all or their cross deposits, while the banks with distance k G {2,3, ..,n 1. — n} some of keep their deposits in the forward neighbor bank. Proposition 3 establishes our main result in this appendix: a liquidity externality, then the cascade size in Propositions 1 and 2. To is much If the banks avoid inflicting shorter relative to the cases analyzed see the intuition, consider the equilibrium in Proposition 3 30 and consider what the banks would do if we removed the government imposed pecking order in assumption (LPO-R). Consider bank demand from its backward neighbor purely by hoarding bank, hoarding reserves delivers 2), (as 1 some • Given the characterization of the losses in the original bank not restricted by government policy, bank cross deposits to hoarding liquidity, which absent government policy, bank 1+n \ which meets its its flexible reserves. R unit of liquidity at an opportunity cost of while withdrawing cross deposits would deliver cost of ^2 bp ^ +n+l bp ^ in 3, 1 it liquidity For (in this period unit of liquidity at an opportunity < R can be checked that q^ will spillover to p ('+") £> liquidity would would put bank bank +n+l bp ^ strictly prefer to ' ) ). Hence, withdraw if its £/('+ n+1 ) in distress. 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