Regime dependent macro models (cont) From Lecture 10 we have the following system of equations: f yt = β0 + β1ert − β2rt + β3gt + β4yt e rt = it − πt+1 Lecture 11: Open economy AD-AS; fiscal policy in different regimes. Ragnar Nymoen Department of Economics, University of Oslo f ert = ∆et + πt − πt + ert−1 πt = πte + γ(yt − ȳ) + st (1) (2) (3) (4) f it = it + ee + αe(∆et + et−1) mt − pt = m0 − m1it + m2yt, mi > 0, i = 1, 2 (5) (6) (1) is the product marked equilibrium condition. (2) is the definition of the e is the expected rate of inflation, one period ahead. real interest rate. πt+1 (3) is a definition equation for ert , see IAM, p 704 and 711. (4) is the PCM. November 6, 2007 1 e /E ) ≡ ee e e (5) is UIP with ln(Et+1 t t+1 − et = e + α (∆et + et−1) inserted. (6) is an equilibrium condition for the money market. Right hand side is a linearization of the demand for money function. 2 interest rate Short-run models f f f In the short-run, the following variables are exogenous: gt, yt , st, πt , it , ert−1, et−1 and pt. Note the discussion at the end of Lecture 10 which motivated the Ei-curve i1 i0 classification of pt as pre-determined (as a simplification). The two main regimes to consider (because the are robust to perfect capital mobility) are Regime I and Regime VI. They are different in terms of how the interest rate is determined. Money M0 M1 E0 E1 exchange rate Regime I: The shift in the Ei-curve does not affect i. E depreciates Regme VI: To avoid depreciation, i is inceased. Accommodated in the money market by reduction of the money supply (through market operations) Figure 1: Regime I and VI: FEX market and money market equilibrium 3 4 Regime I (floating ex rate) Regime VI (fixed ex rate, it as instrument) Regime dependent exogenous variable: mt Regime dependent exogenous variable: ∆et. n f yt = β0 + β1 ∆et + πt − πt + ert−1 n f o o (7) f e + β3gt + β4yt − β2 it + ee + αe(∆et + et−1) − πt+1 e πt = πt + γ(yt − ȳ) + st f it = it + ee + αe(∆et + et−1) mt − pt = m0 − m1it + m2yt Money market and FEX market is now interlocked. Solve (5) and (6) for it and the nominal exchange rate: 1 f (it − it − ee) − et−1 αe −1 m m it = (mt − pt) + 0 + 2 yt m1 m1 m1 ∆et = (8) (9) (10) (7) is the AD curve. Note that the equilibrium condition on the market for e , foreign exchange, (9), is included in this equation. (8) is the AS curve. If πt+1 e and πt are exogenous, then (7) and (8) determine yt and πt. it is determined in (9) and mt in (10). ( ( ) m m 1 f −1 f (mt − pt) + 0 + 2 yt − e (it + ee) + πt − πt m1 m1 m1 α ( ) m0 m2 −1 e − β2 (mt − pt) + + yt − πt+1 m1 m1 m1 yt = β0 + β1 1 αe f + β3gt + β4yt ) (11) πt = πte + γ(yt − ȳ) + st (12) 6 5 The difference between Regime I and VI is the slope of the AD curves (7) and (11): ¯ ∂πt ¯¯ 1 = <0 ¯ ∂yt ¯AD,rV I −β1 (13) ¯ m1 2 1 − β1 αm e m + β2 m ∂πt ¯¯ 1 2 = (14) ¯ ∂yt ¯AD,rI −β1 We noted that (14) hinges on αe 6= 0. The interpretation is that with constant depreciation expectations and perfect capital mobility, it is determined by the UIP condition alone. Hence αe = 0 would introduce an internal inconsistency with the assumption that in this regime, mt is exogenous. We ended Lecture 10 by the following important result about the slopes of the short-run AS curves of the two regimes. ¯ ¯ ∂πt ¯¯ ∂πt ¯¯ >− , when αe < 0 − ¯ ¯ ¯ ∂yt AD,rI ∂yt ¯AD,rV I (15) Interpretation of slope-difference The interpretation of the difference has to do with how the interest rate is determined in the two regimes: When πt increases, y-demand is reduced in both regimes through the real exchange rate, er . But there are additional effects in RI: Lower demand for money reduces the interest rate in the domestic money market. Hence the eventual reduction in y-demand in RI is less than in RVI. This is the same as saying that the slope of the AD curve is steeper in RI than in RVI. ¯ ¯ ∂πt ¯¯ ∂πt ¯¯ − >− ¯ ¯ ∂yt ¯AD,rI ∂yt ¯AD,rV I meaning that the slope of the short-run AD curve is steeper in Regime I than in Regime VI, at least when αe < 0. 7 8 p The short-run solutions for πt and yt is obtained by solving (11) and (12), for Regime I, and (7) and (8) for Regime VI. To learn about the properties of the two regime versions of the model we will consider the response of the endogenous variables yt and πt. Regime VI For simplicity, and according to custom, we assume that the initial situation is characterized by πt = π e Regime I and yt = ȳ, y e Figure 2: Short-run AD curves, fixed πt+1 in regime I and VI. as depicted in figure 3. 10 9 Fiscal policy in RI and RVI p Consider the immediate (short-run) effect of an increase in gt. AS p From (11) and (7), note that for a given yt, the derivative of πt with respect to gt is identical in the two regimes e ¯ RVI RI y y e . Regime I and VI. Figure 3: Initial situation with πt = πt+1 11 ¯ dπt ¯¯ β dπt ¯¯ = = 3>0 ¯ ¯ ¯ dgt yt=ȳ,rI dgt ¯yt=ȳ,rI β1 The graphical analysis of short-run effects of fiscal policy is therefore represented by identical vertical shifts in the AD curve of the two regimes. Hence, the impact effect of increased gt is larger in Regime VI (fixed exchange rate) than in Regime I (float), see figure 4. The explanation is that higher GDP output increases the demand for money, which in Regime I increases the interest rate, in regime VI the interest rate stays constant. 12 p AS Long-run models RVI RI pe We still consider Regime I and VI, and repeat the equations of the model: f yt = β0 + β1ert − β2rt + β3gt + β4yt (16) ert = (18) rt = y y πt = it = e it − πt+1 f ∆et + πt − πt + ert−1 e πt + γ(yt − ȳ) + st f it + ee + αe(∆et + et−1) e Figure 4: Short-run effects of fiscal policy, regime Regime I and VI, fixed πt+1 and πte . mt − pt = m0 − m1it + m2yt, mi > 0, i = 1, 2 13 14 (17) (19) (20) (21) Hence, from the UIP condition (20): The models’ steady-state is defined by the following, see IAM p. 717-719. πte = π̄ f , expectation equal to the world inflation rate yt = ȳ, ert = ert−1 = er , stationarity of rex, gt = ḡ, gov exp on trend, f yt = ȳ f , world GDP on trend ı̄f = constant world interest rate st = 0, no supply shocks Since ert = ert−1 = er and πt = π̄ f it follows from (18) that ∆et = 0 in e /E ) so we add steady-state. It is logical that in a steady-state ∆et = ln(Et+1 t e /E ) = ∆e = 0 ln(Et+1 t t to the list of steady-state conditions. i = ı̄f (22) m − p = m0 − m1ı̄f + m2ȳ (23) ȳ = β0 + β1er − β2(ı̄f − π̄ f ) + β3ḡ + β4ȳ f , from AD π = π f , from AS (24) (25) and from (21) e = π̄ f in (16) gives Using i = ı̄f and πt+1 The equations of the long-run model are thus: (24),(25), (22) and (23). The endogenous variables of the long-run model are: er , π, i, m or e, and p. Even though pt is predetermined in the short-run model it is endogenous in the long-run. Hence there is one missing equation in our long-run model. However, note that ert = ert−1 = er is actually the hypothesis of PPP, as a long-run property. Hence, from the definition of er p = e + pf − er 15 16 (26) which determines p (noting that er is determined in the (24) and pf is exogenous. The PPP condition (26) determines p in the Regime VI since e is exogenous and fixed. e /E ) = 0 which In regime I, e is determined from the long run condition ln(Et+1 t gives Hence, if the increase in g is permanent, the model predicts a long-run there real appreciation. In both regimes, we can think as if this takes place trough increased P , i.e. using (26). 0 = ee + αee and e in Regime 1. Hence, in the long-run model, p is determined by PPP also in regime I. Hence, m is assumed to be endogenous in the long-run version of regime I. Regime independency of the long-run solution (IAM figure 23.7) However, as advanced courses on flexible exchange rates will show, the stability of the nominal dynamic adjustment process in regime I is not straight-forward. The dynamics for regime VI is easier to analyze explicitly, and we do that in the next lecture. (24) is the same in both regimes (I and VI). The long-run AS schedule is also identical across the two regimes. Hence the steady-state solutions for er and π are independent of the two regimes. ¯ der ¯¯ −β3 = <0 ¯ dḡ ¯rI,rV I β1 18 17 e r e r LR AS LRAD Short-summary of our analysis of the AD-AS model so far. r e0 y y Float/fix Target (exogenous) Instrument short-run effects of g long-run effects of g RI R VI float M i yt and πt ↑, er ↓ er ↓, fix E i larger on yt and πt same as RI Figure 5: Long-run effect of fiscal policy, regime Regime I and VI . 19 20 Summary of regime dependent open economy macro model so More on fiscal policy in the fixed exchange rate regime far We have analyzed the short-run and long-run effects of a permanent change in gt in two exchange rate regimes: Float with money supply as exogenous target variable, and fixed with Et as exogenous target variable and i as instrument. The above is based on fixed and exogenous inflation and a permanent policy change. We now relax these assumptions, and we also want to say something about dynamics. a. Change in gt is permanent and πte and πte are constant Main conclusions: 1. The regimes can be graphically represented in one graph: the slopes of the AD lines are different. Steeper in the floating ex-rate regime 2. Short-run effect of fiscal policy expansion largest in case of fixed ex-rate regime 3. No long-run effects on y in either regime. The new long run equilibrium level of ert is lower than before the shock. Nominal appreciation in the case of float. Increased P in the fixed exchange rate regime. Short-run: AD curve shifts. Dynamics: AD curve shift gradually back again. e The economy is “gliding” back to initial equilibrium point (πt+1 = πte = π f r and yt = ȳ). Gradually et is reduced. e b. As in case a) but inflation expectations are rational in the sense of πt+1 = e f πt = π , see page 739 in IAM. Same analysis! 21 Formal analysis of dynamics and stability 22 The model can be written in somewhat more compact form as f yt − ȳ = β̂0 − β1(πt − πt ) + β1ert−1 + β3gt + dt, f f f dt = −β2(it − πt ) + β4yt − ȳ See 739-741 in ch 24.3 of IAM. f So far we have implitely assumed that the dynamic process which is triggered by the raise in gt is stable, so that a new long-run equilibrium is reached. Intuitively, the dynamics are in fact stable, since a process of real currency appreciation is begins as a result of the shock. As an exercise, this can be shown formally. πt − πt = γ(yt − ȳ) + st f ert = −(πt − πt ) + ert−1 Use (27) and (28) to express for ert−1 by yt − ȳ (e.g. f (πt − πt )): ert−1 = Fixed ex-rate assumptions: (27) (28) (29) by substitution for 1 β dt β̂ (1 + β1γ)(yt − ȳ) + st − 3 gt − − 0 β1 β1 β1 β1 which is equation (17) page 739. We also have: e πt+1 = πte = π f eet+1 − et = 0 ∆et = 0 23 ert = 1 β d β̂ (1 + β1γ)(yt+1 − ȳ) + st+1 − 3 gt+1 − t+1 − 0 β1 β1 β1 β1 Using these two expressions in (29), together with (28), gives the following 24 ADL model for (yt+1 − ȳ): (yt+1 − ȳ) = 1 β3 (yt − ȳ) + ∆gt+1 + .... 1 + β1γ (1 + β1γ) Temporary versus permanent fiscal policy shocks (IAM p 24.3) or, for yt : (30) We can also use (30) to analyze the different responses to permanent and temporary fiscal policy shocks. We can now apply what we have learnt about stability earlier, namely that (yt − ȳ) is dynamically stable if A permanent shock amounts to ∆g1 > 0, for example ∆g1 = 1, and ∆g2 = ∆g3 = ... = 0. (yt − ȳ) = 1 β3 (yt−1 − ȳ) + ∆gt + .... 1 + β1γ (1 + β1γ) 1 <1 1 + β1γ A temporary shock amounts to ∆g1 = 1, ∆g2 = −1, for example, and ∆g3 = which holds since β1γ > 0. 25 26 ∆g4 = ... = 0. perm temp impact β3 (1+β1γ) β3 (1+β1γ) 2nd β3 (1+β1γ)2 −β1γβ3 (1+β1γ)2 Intuitively, in this model, systematic fiscal policy leads to a steeper short-run AD schedule. A real appreciation leads to less reduction in y in the case of a > 0, than a = 0, see fig 24.4. 3rd β3 (1+β1γ)3 −β1γβ3 (1+β1γ)3 Effects of negative demand shocks are smothered. ... 0 ... 0 The speed of adjustment is reduced. Hence the temporary leads to a short expansion, and then a longer period where yt − ȳ < 0. So far we have considered unsystematic fiscal policy, An example of systematic fiscal policy is: gt − ḡ = a(ȳ − yt), 27 a > 0. (31) 28