Part IV. Other market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Microeconomics IV Part IV. Other market failures: Imperfect Information Professor: Marc Teignier Baqué Universitat de Barcelona, Facultat de Ciències Econòmiques and Empresarials, Departament de Teoria Econòmica Second Semester, Course 2021-2022 Part IV. Other PART IV. IMPERFECT INFORMATION market failures: Imperfect Information Uncertainty Adverse selection Moral hazard I First Welfare Theorem: all competitive equilibrium allocations are Pareto ecient (invisible hand mechanism). I Assumptions behind it: I I I I markets are competitive, no externalities, perfect information. Market failures: I I I consumption/production externalities, public goods, asymmetric information. Part IV. Other Part III Contents market failures: Imperfect Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard 1. Choice under uncertainty 1.1 State-contingent budget constraints 1.2 Preferences under uncertainty 1.3 Choice under uncertainty 1.4 Fair insurance 1.5 Risk diversication 2. Asymetric information: adverse selection 3. Asymetric information: moral hazard Part IV. Other market failures: Imperfect TOPIC 9. CHOICE UNDER UNCERTAINTY I Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard So far, optimization problems considered had no uncertainty. I However, in the real world people often make decisions with uncertainty about future prices, future wealth, or other agents' decisions. I In this section, we study the choice problem under uncertainty using a two-state version of our consumer's choice model. I Optimal responses: insurance purchase, risk diversication. I Example: I 2 possible states of nature: car accident (loss of L¿), no car accident. I I Probabilities for each state: Insurance: get K¿ insurance premium. πa , πna . if accident by paying γK ¿ as Part IV. Other State-contingent budget constraints market failures: Imperfect Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard Denitions A contract is state contingent if it is implemented only when a particular state of Nature occurs. A state-contingent consumption plan species the consumption to be implemented when each state of Nature occurs. I Example: I I Consumption if no accident: cna = M − γK Consumption if accident: ca = M − L − γK + K ⇒ K = ca −M +L 1−γ ca − M + L 1−γ γ M − γL ⇔ cna = − ca 1−γ 1−γ ⇒ cna = M − γ Part IV. Other market failures: Imperfect Information Uncertainty State-contingent budget constraints Car Insurance example I State-contingent budget constraint in car insurance example: Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard cna = γ m − γL − ca 1−γ 1−γ | {z } | {z } intercept slope Cna Bundle with no consumption if accident: K M LM 1 Endowment bundle Full insurance bundle (Ca =Cna ) Bundle with no consumption if no accident: K M M‐L Ca Part IV. Other market failures: Imperfect Preferences under Uncertainty I Information their preferences about the dierent state-contingent Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard To know what is the agents' choice, we need to know consumption plans. I Utility across state-contingent consumption plans is a function of the consumption levels and probabilities at each state,U (c1 , c2 , π1 , π2 ). Denition A utility function utility or U (c1 , c2 , π1 , π2 ) satises the von NeumannMorgenstern expected property if it can be written as the weighted sum of the utility at each state, where the weights are the probabilities of each state: U (c1 , c2 , π1 , π2 ) = π1 v (c1 ) + π2 v (c2 ) It satises the independence property, which means that the utility in a given state is independent of the utility in other states. Part IV. Other Risk aversion market failures: Imperfect Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Denition We say an agent is risk averse if the expected utility of wealth is lower than the utility of expected wealth, if it is higher, and I Adverse selection Moral hazard risk neutral Example: I I I I Lottery: 90 risk lover if it is equal. ¿ with probability 1/2, 0¿ with prob 1/2. Utility levels: U($90) = 12, U($0) = 2. Expected utility: EU=1/2*12+1/2*2=7. Expected money value: EM=1/2*90+1/2*0=45. Risk lover consumer Risk averse consumer Risk neutral consumer 12 12 EU 7 EU=7 U(45) EU 7 U(45)=EU=7 12 U(45) EU=7 U(45) 2 2 0 45 90 W lh Wealth 2 0 45 90 Wealth 0 45 90 Wea Part IV. Other Indierence Curves market failures: Imperfect Information I expected utility are equally preferred and on the same Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard State-contingent consumption plans that give equal indierence curve. I Slope of indierence curves: EU = π1 U (c1 ) + π2 U (c2 ) ⇒ dEU = π1 π1 ∂ U (c1 ) ∂ U (c2 ) dc1 + π1 dc2 ∂ c1 ∂ c2 π1 ∂ U (c1 ) /∂ c1 ∂ U (c1 ) ∂ U (c2 ) dc2 dc1 + π2 dc2 = 0 ⇒ =− ∂ c1 ∂ c2 dc1 π2 ∂ U (c2 ) /∂ c2 C2 Indifference curves EU1 < EU2 < EU3 EU3 EU2 EU1 C1 Part IV. Other market failures: Imperfect Choice under uncertainty I Information Uncertainty Contingent BC Preferences Choice Insurance Diversication The optimal choice under uncertainty is the most preferred aordable state-contingent consumption plan. I In the car insurance example, the optimal consumption plan is where the slope of indierence curves is tangent to the budget constraint: Adverse selection Moral hazard γ πa ∂ U (ca ) /∂ ca = πna ∂ U (cna ) /∂ cna 1 − γ Cna Most preferred affordable plan m Affordable plans m L m L Ca Part IV. Other Fair insurance market failures: Imperfect Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard Denition We say an insurance is fair or competitive if the expected economic prot of the insurer is zero, or, equivalently, if the ¿ insurance is the probability of the insured state. price of a 1 I Car insurance example: γK |{z} −πa K − (1 − πa ) 0 {z } | = 0 ⇒ γ = πa revenues expected expenditures I If the insurance is fair, the optimal choice of risk-averse consumers is full insurance: πa ∂ U (ca ) /∂ ca πa ∂ U (ca ) ∂ U (cna ) = ⇒ = πna ∂ U (cna ) /∂ cna 1 − πa ∂ ca ∂ cna Hence, for risk averse consumers, ca = cna . Part IV. Other market failures: Imperfect Information Uncertainty Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard Unfair insurance Unfair Insurance Denition We say an insurance is unfair if the insurer makes positive expected economic prots. I If the insurance is unfair, the optimal choice of risk-averse consumers is less than full insurance: γK |{z} −π K − (1 − πa ) 0 | a {z } >0⇒ revenues expected expenditures Hence, πa ∂ U(ca )/∂ ca πna ∂ U(cna )/∂ cna γ = 1−γ implies that ∂ U (ca ) ∂ U (cna ) > ∂ ca ∂ cna so, for risk averse consumers,ca < cna . πa γ > 1−γ πna Part IV. Other Diversication market failures: Imperfect Information I Uncertainty earnings in exchange for lowered risk. This is going to Contingent BC Preferences Choice Insurance Diversication Adverse selection Moral hazard Asset diversication typically lowers (or keeps) expected be the case as long as the asset prices are not perfectly correlated across states. I Example: two rms, two states (prob. 1/2), agent with 100 ¿ to spend in rms' share. I ¿, in state 2 20¿. 100 I ¿, prots per share in state 1 Firm A: shares' cost 10 ¿, prots per share in state 1 Firm B: shares' cost 10 ¿, in state 2 100¿. 20 Prots in 1 Prots in 2 Expected prots 10 shares of A 10 shares of B 5 of A, 5 of B 200¿ 1000¿ 600¿ 1000¿ 600¿ 200¿ 600¿ 600¿ 600¿ Part IV. Other Part III Contents market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling Moral hazard 1. Uncertainty 2. Asymetric information: adverse selection and signaling 2.1 The model of Akerlof 2.2 Signaling 3. Asymetric information: moral hazard Part IV. Other ASYMETRIC INFORMATION market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling I In the purely competitive markets, agents are assumed to have perfect information about all the exchange aspects. I In some markets, however, this is clearly not realistic (medical services, used cars, insurance...): Moral hazard I I A doctor knows more about medicine than the patient. A used car seller has more information about the car than the potential buyer. I The buyer of an insurance knows much more about his/her risks than the insurer. I We say that a market suers from information imperfect if one of the sides does not have all the information about the exchange. I We say that a market suers from information asymetric if one of the sides has more information than the other. Part IV. Other Asymetric information ineciency market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling I Under asymetric information, markets typically have less transactions than under the perfect information Moral hazard equilibrium; hence, we say that the equilibrium under asymetric information is inecient. I In this context, government intervention may be Pareto improving but it may also be Pareto worsening. I The question is, then, whether government has more information than market participants and whether the costs associated to it are not too large. Part IV. Other Asymetric information applications market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling Moral hazard I Adverse selection refers to a situation where one of the sides cannot observe all the characterstics of a good (also known as I Signaling hidden quality problem ). refers to a situation where the high/quality agent takes actions to dierent him/herself from the rest of agents. I Moral hazard refers to a situation where one of the sides cannot observe the actions of the other side (also known as hidden action problem). I Incentives contracting consists on designing a system of incentives to prevent agents from taking undesired actions after the contract is signed. Part IV. Other TOPIC 10. ADVERSE SELECTION market failures: Imperfect Information Uncertainty Adverse selection I Consider a used-cars market with two types of cars, lemons and peaches: I Adverse selection Signaling The reservation price of lemons sellers is 1000, while buyers are willing to pay 1200. Moral hazard I The reservation price of peaches sellers is 2000, while buyers are willing to pay 2400. I Therefore, when sellers have perfect information all the cars get sold and the total surplus is positive: I Lemons are sold for an amount between 1000 and 1200. I Peaches are sold for an amount between 2000 and 2400. I But what happens when sellers do not know the car type? Part IV. Other Akerlof model market failures: Imperfect Information Uncertainty Adverse selection I If buyers cannot distinguish lemons and peaches (but they know the proportions), how much are they willing to pay? I Adverse selection Signaling Let q denote the fraction of high-quality cars and 1 − q the low-quality ones. Moral hazard I Therefore, the expected value for the buyer is V e = 1200(1 − q) + 2400q . I When I I I I q is such that V e < 2000, The high-quality sellers leave the market. Only the low-quality sellers stay in the market. Knowing this, buyers are only willing to pay 1200. Hence, too many low-quality cars are expelled from the market, which reduces the exchange surplus. In other words, the presence of low-quality sellers imposes an external cost to high-quality sellers and buyers. Part IV. Other Akerlof model (2) market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling I How many low-quality cars are compatible with high-quality cars remaining in the market? Moral hazard I Buyers are willing to pay 2000 if q is such that V e = 1200(1 − q) + 2400q ≥ 2000. I Hence, if q < 13 , only low-quality cars are sold. I Pooling and seprating equilibrium: I In a separating equilibrium only of type of cars is traded or each type is traded at a dierent price. I In a pooling equilibrium the same price. both types of cars are sold at Part IV. Other Adverse selection with a continuum of types market failures: Imperfect Information Uncertainty Adverse selection I If the car quality x is uniformly distributed between 1000 and 2000 and buyers are willing to pay Adverse selection Signaling x + 300 for a car of quality x. Moral hazard I Which cars are traded in this case? I The expected quality is 1500 and the expected value for sellers is 1500 + 300 = 1800. I I Hence, sellers of quality above 1800 leave the market. As a result, the expected value for the cars remaining in the market becomes $1400 + $300 = $1700. I As a result, the sellers with quality between 1700 and 1800 abandon the market.. I ... Part IV. Other Adverse selection with a continuum of types (2) market failures: Imperfect Information Uncertainty Adverse selection I Which cars will remain in the market? I Adverse selection Signaling Denote vH the quality (or seller's value) of the best car in the carel valor. Moral hazard I I I The expected quality of the cars in the market is, thus, V e = 1000 + vH −21000 = + v2H . Hence, the expected value for the seller is 1000 2 + v2H + 300. Since this will also be the highest quality in the market, 1000 2 I 1000 2 + vH 2 + 300 = vH ⇒ vH = 1600 Therefore the adverse selection expels all the cars with quality above 1600. Part IV. Other Adverse selection with quality choice market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling Moral hazard I Suppose now that sellers can choose the quality of the product they sell. I Example: two types of umbrellas, high quality and low quality (not dierentiable for the consumer). I Buyers' valuation is 14 for the high quality and 8 for the low quality. I Production cost is 11 for the high quality and 10 for the low quality. I Is there any equilibrium in this market? Part IV. Other Adverse selection with quality choice (2) market failures: Imperfect Information Uncertainty Adverse selection I Adverse selection Signaling Is it possible an equilibrium where only low-quality umbrellas are sold? I Moral hazard I No, because sellers would have a benet equal to -2. Is it possible an equlibrium where only the high-quality umbrellas are produced? I If there are only high-quality umbrellas, buyers are willing to pay 14 and sellers obtain a prot of 3. I But sellers can have a benet equal to 4 by producing low quality umbrellas. I Hence, it is not possible to only have high-quality producers. Part IV. Other Adverse selection with quality choice (3) market failures: Imperfect Information Uncertainty Adverse selection I Is it possible to have an equilibrium where both types are produced? I Adverse selection Signaling Let q denote the fraction of sellers producing high quality, where 0 Moral hazard I < q < 1. Then, the buyers' expected value is V e = 14q + 8(1 − q) = 8 + 6q . I Since the high quality producers must have positive prots, 8 + 6q I > 11q + 10 (1 − q) ⇒ q > 2/5. But note that sellers can always increase their prots by producing only low quality. I I And when q=0 buyers are only willing to pay 8. There, an equilibrium with both types does not exist either! I In this situation, the adverse selection problem completely destroys the market! Part IV. Other market failures: Imperfect Signaling I Information Uncertainty Adverse selection Adverse selection Signaling In a context with adverse selection, high-quality sellers have an incentive to signal their quality: I I Methods: reference letters, warranties, advertisement. Example: labor market with high ability type and low ability type. Moral hazard I The marginal product of the high ability type is aL < aH . I The fraction of high ability workers is h, while fraction of low ability workers i 1 − h. the low ability type is I aL , aH and where the If rms can distinguish the two types (and workers are paid their marginal product) wH = aH , wL = aL . I But if rms cannot dierentiate the two types, they will oer workers the expected marginal product: wP = (1 − h)aL + haH . I Since wP = (1 − h)aL + haH < aH , high-quality workers may be willing to pay to send a credible signal. Part IV. Other market failures: Imperfect Information Education as a signal I I Uncertainty Adverse selection Denote the education cost by workers and I Adverse selection Signaling Moral hazard Workers may want to use education as a signal: cL cH for high-education for low-education workers, with cL > cH . Assume (just as a example!) that education does not change the productivity of workers. I High-abilty agents want to get eH units of education if it works as a signal: I the benet is higher than the cost for high-ability workers: I wH − wL = aH − aL > cH eH , the benet is higher than the cost low-ability workers: wH − wL = aH − aL < cL eH . I In this situation, high-ability workers want to get education while low-ability workers do not. I Therefore, education is useful to signal the type. I Note that signaling solves the information asymetry problem but at a cost. Part IV. Other market failures: Imperfect Warranties as a signal I Information Example: used-cars market with high and low quality cars: I Uncertainty Adverse selection High-quality cars: sellers are willing to sell for 8 000, buyers are willing to pay 10 000. I Adverse selection Signaling Low-quality cars: sellers are willing to sell for 5 000, buyers are willing to pay 6 000. Moral hazard I Suppose sellers have the possibility of oering a warranty, which costs 500/year for high-quality car owners and 2000/year for low-quality car owners.. I Is there any warranty duration n such that only high-quality owners are interested in it? I High-quality owners are interested in oering it if 10000 − 500n I ≥ 6000 Low-quality owners are not interested in oering it if 10000 − 2000n I Hence, if 2 < n ≤ 4, < 6000 a warranty allows low-quality sellers to dierentiate themselves. Part IV. Other Advertising as a signal market failures: Imperfect Information Uncertainty Adverse selection Adverse selection Signaling I Consider now a market with asymetric information and high and low quality sellers. I Moral hazard Suppose that consumers purchase the good only once if the quality is low and several times if quality is high. I One possible way to signal the high-quality is to make launching sales or oer free samples. I Another signaling option is to advertise the product; this is the case if there an advertising expenditure G that: I G is lower than the extra benets obtained by high-quality sellers due to the advertisement. I G is higher than the extra benets obtained by low-quality sellers due to advertisement. such Part IV. Other Part III Contents market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages 1. Uncertainty 2. Asymetric information: adverse selection and signaling 3. Asymetric information: moral hazard and incentives contracting 3.1 The principal-agent model 3.2 Incentives contracting 3.3 Eciency wages Part IV. Other market failures: Imperfect TOPIC 11. MORAL HAZARD I Information Uncertainty Adverse selection Moral hazard Moral hazard is the agents' optimal response to a change in the risk loss and it is consequence of the asymetric information. I For example, when someone buys a bike theft insurance, it he/she more likely to leave the bike unlocked? Moral hazard Incentives contracting Eciency wages I In case of robbery, the cost is lower when insurance purchased, so the incentives to protect are lower. I It is then a situation where I the lack of insurance is inecient because there is an exogenous theft risk and consumers are risk averse, I but the insurance can also create other ineciencies if agents modify their behavior. I I Insurers try to reduce the moral hazard problem: I I Health insurance premium is higher for smokers; Car insurance premium is lower for drivers with a good record of accidents. Part IV. Other The principal-agent model market failures: Imperfect Information Uncertainty Adverse selection Moral hazard I Consider a situation where I a worker (agent) is hired by an employer (principal) to perform a job; Moral hazard Incentives contracting Eciency wages I there is a conict of interests between the principal and the agent: the principal wants a high eort by the agent to maximize benets, while the agent does not like eort; I I eort is not observable. The objective is to analyze how the principal can give the agent the right incentives. I Other principal-agent examples: lawyer and customer, auto repair shop and customer. Part IV. Other Incentives contracting market failures: Imperfect Information Uncertainty Adverse selection Moral hazard I The problem of the principal : design the incentives contract to encourage an optimal eort by the worker. I Let e denote the eor of the agent and y = f (e) the revenues of the principal. Moral hazard Incentives contracting Eciency wages I An incnetives contract s(y ) species the worker compensation as a function of the principal revenues, I y. In this context, the principal benets are πp = y − s (y ) = f (e) − s (f (e)) . I At the same time, the principal has to take into account the agent participation constraint, so that the worker gets at least his/her reservation utility. I I Denote by Denote by ũ the worker's reservation utility. c (e) the cost of exerting the eort e . Part IV. Other Incentives contracting (2) market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages I The principal optimization problem is, then: maxπp = f (e) − s (f (e)) e s.t. I s (f (e)) − c (e) = ũ (participation constraint) The optimal contract species an eort level e∗ such that the marginal benet of the principal is equal to the marginal cost of the worker: I f 0 (e ∗ ) = c 0 (e ∗ ) How to encourage to worker to choose I The contract s(y ) e = e ∗? has to satisfy the incentive compatibility constraint : s (f (e ∗ )) − c (e ∗ ) ≥ s (f (e)) − c (e) for any e ≥0 Part IV. Other Incentives contracting (3) market failures: Imperfect Information I Uncertainty Adverse selection Moral hazard Commercial rental contracts: I keeps all the extra prots: I Moral hazard Incentives contracting Eciency wages R and the worker s (f (e)) = f (e) − R . The principal asks for a xed rent Thus, the worker maximizes its revenues s (f (e)) − c (e) = f (e) − R − c (e), and chooses the ∗ 0 ∗ 0 ∗ ecient eort level e such that f (e ) = c (e ). I The principal will choose the highest possible R ∗ considering the agent participation constraint f (e ∗ ) − R ∗ − c (e ∗ ) = ũ I Variable wage contracts (assuming that e is observable even if it is not veriable): I I If I The principal then choosesK such that the participation Set the agent pay equal to w = f 0 (e ∗ ), ∗ level e . s (e) = we + K . the worker chooses the optimal eort constraint is satised. Part IV. Other Eciency wages market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages I To motivate workers to choose a high eort, a rm may be willing to pay wage above the equilibrium level. I If workers do not perform well and they are red, they will earn a lower wage in the next job. I If all rms choose to pay eciency wages, the mechanism still works: there is unemployment so, if red, workers will not nd a job immediately. I Eciency wages are likely to reduce the monitoring costs of rms as well as their hiring costs. I In a context with adverse selection, they may also be useful to attract the most talented workers. Part IV. Other A model with eciency wages market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages I The worker utility is is high, and I √ w −g, where g =2 if eort if eort is low. The probability that the worker is caught doing a low eort is I g =1 U= q. If the wage oered by the rm is one is I w∗ and the equilibrium w0 , the participation constraint is √ √ √ √ w ∗ − 2 ≥ w0 − 1 ⇔ w ∗ ≥ w0 + 1, I and the incentive compatibility constraint is √ √ √ w ∗ − 2 ≥ q ( w0 + 1) + (1 − q) w∗ −1 ⇔ √ √ 1 w ∗ ≥ w0 + . q Part IV. Other market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages Unemployment benets in the eciency wages model I Suppose now that if the worker loses her job, there is a probability 1 − t to become unemployed, with unemployment subsidy I d. In this situation, the incentive compatibility constraint is √ √ √ √ w ∗ − 2 ≥ q t ( w0 − 1) + (1 − t) d + (1 − q) w∗ −1 ⇒ I √ √ √ √ 1 w∗ = t w0 − 1 − d + d + + 1 q As a result, I t ↑ ⇒ w ∗ ↑. I d ↑⇒ w ∗ ↑. Part IV. Other Other situations with moral hazard market failures: Imperfect Information Uncertainty Adverse selection Moral hazard I Moral hazard Incentives contracting Eciency wages Insurance: when people get an insurance they are less likely to be cautious. I To reduce the moral hazard problem, insurance companies introduce a deductible F (paid by the agent in case of accident). I Bank loans and investment projects: I Firms may choose a risky project once they get the loan because they don't have to pay back in case of failure. Part IV. Other Other incentives contracting examples market failures: Imperfect Information Uncertainty Adverse selection Moral hazard Moral hazard Incentives contracting Eciency wages I Sales commissions: real state agents, insurance sellers... I Up or out rm policy: members must leave the organization if they fail to achieve a certain rank within a certain period of time. I Rankings of workers. I Why don't we observe more incentives contracting examples: I Incentive schemes may not work as planned: to little quality if reward to production quantity. I Free riding. problems when production by teams instead of individuals. I I Jobs with multiple tasks. Participation of trade unions in design of job contracts. THE END