Central Banks Balance Sheet Policies Without Rational Expectations Luigi Iovino Dmitriy Sergeyev Bocconi University, IGIER, CEPR ESSIM 2019 - Tarragona May 7, 2019 1
Central Banks Balance Sheet PoliciesWithout Rational Expectations
Luigi Iovino Dmitriy Sergeyev
Bocconi University, IGIER, CEPR
ESSIM 2019 - Tarragona
May 7, 2019
1
Central Banks Balance Sheet Policies
Examples
I QE (long-term public and private assets purchases)
I FX interventions
“The problem with QE is that it works in practice,but it does not work in theory”
Ben Bernanke (2014)
2
Central Banks Balance Sheet Policies
Examples
I QE (long-term public and private assets purchases)
I FX interventions
“The problem with QE is that it works in practice,but it does not work in theory”
Ben Bernanke (2014)
2
Empirics
QE
I Gagnon-Raskin-Remache-Sack (2011),Krishnamurthy-Vissing-Jorgensen (2011),Hancock-Passmore (2011), Di Maggio-Kermani-Palmer(2016), Chakraborty-Goldstein-MacKinlay (2016),Fieldhouse-Mertens-Ravn (2018)
, Stroebel-Taylor(2012),Greenlaw-Hamilton-Harris-West (2018)
FX interventions
I Dominguez-Frankel (1990, 1993), Dominguez (1990, 2006),Catte-Galli-Rebecchini (1994), Kearns-Rigobon (2005),Blanchard-Adler-de Carvalho (2014),Fratzscher-Gloede-Menkhoff-Sarno-Stohr (2015)
Beine-Benassy-Quere-Lecourt (2002)
3
Empirics
QE
I Gagnon-Raskin-Remache-Sack (2011),Krishnamurthy-Vissing-Jorgensen (2011),Hancock-Passmore (2011), Di Maggio-Kermani-Palmer(2016), Chakraborty-Goldstein-MacKinlay (2016),Fieldhouse-Mertens-Ravn (2018), Stroebel-Taylor(2012),Greenlaw-Hamilton-Harris-West (2018)
FX interventions
I Dominguez-Frankel (1990, 1993), Dominguez (1990, 2006),Catte-Galli-Rebecchini (1994), Kearns-Rigobon (2005),Blanchard-Adler-de Carvalho (2014),Fratzscher-Gloede-Menkhoff-Sarno-Stohr (2015)Beine-Benassy-Quere-Lecourt (2002)
3
Theory
The irrelevance result
if
1. people can freely trade targeted assets
2. symmetric info between policy maker and markets
3. people correctly predict future effects of policies
Prominent channels
1. Portfolio balance channel (segmented markets)
2. Signaling channel (asymmetric info or limited commitment)
This paper: bounded rationality channel
I Beliefs about future deviate from rational expectations
I Agents do not fully understand future effects of the policies
4
Theory
The irrelevance result if
1. people can freely trade targeted assets
2. symmetric info between policy maker and markets
3. people correctly predict future effects of policies
Prominent channels
1. Portfolio balance channel (segmented markets)
2. Signaling channel (asymmetric info or limited commitment)
This paper: bounded rationality channel
I Beliefs about future deviate from rational expectations
I Agents do not fully understand future effects of the policies
4
Theory
The irrelevance result if
1. people can freely trade targeted assets
2. symmetric info between policy maker and markets
3. people correctly predict future effects of policies
Prominent channels
1. Portfolio balance channel (segmented markets)
2. Signaling channel (asymmetric info or limited commitment)
This paper: bounded rationality channel
I Beliefs about future deviate from rational expectations
I Agents do not fully understand future effects of the policies
4
Theory
The irrelevance result if
1. people can freely trade targeted assets
2. symmetric info between policy maker and markets
3. people correctly predict future effects of policies
Prominent channels
1. Portfolio balance channel (segmented markets)
2. Signaling channel (asymmetric info or limited commitment)
This paper: bounded rationality channel
I Beliefs about future deviate from rational expectations
I Agents do not fully understand future effects of the policies
4
Roadmap
1. A simple real closed-economy model
2. Full model with endogenous output
3. Empirical evidence
5
Deviations from Rational Expectations
Induction
I Idea: beliefs about future are refined over time through aprocess of induction from observed outcomes.
I Econometric learning : Evans-Honkapohja; Shleifer; etc.
Eduction
I Idea: agents understand the model and form expectationsfrom it about future outcomes through the process ofreflection
I Level-k thinking
6
Deviations from Rational Expectations
Induction
I Idea: beliefs about future are refined over time through aprocess of induction from observed outcomes.
I Econometric learning : Evans-Honkapohja; Shleifer; etc.
Eduction
I Idea: agents understand the model and form expectationsfrom it about future outcomes through the process ofreflection
I Level-k thinking
6
Deviations from Rational Expectations
Induction
I Idea: beliefs about future are refined over time through aprocess of induction from observed outcomes.
I Econometric learning : Evans-Honkapohja; Shleifer; etc.
Eduction
I Idea: agents understand the model and form expectationsfrom it about future outcomes through the process ofreflection
I Level-k thinking
6
Level-k Thinking
Game Theory
I Stahl-Wilson (1994,1995); Nagel (1995); Crawford (2013)
I Idea: Agents know the game; rationally respond to beliefs;form beliefs about opponents actions recursively
I Result: Level-k thinking better approximates experimentalresults in strategic games (more so in new games)
Macro
I Evans-Ramey; GarciaSchmidt-Woodford; Farhi-Werning
I Idea: Agents know the model; optimize; form expectationsabout future endogenous variables recursively
I Result: Level-k thinking dampens changes in expectationsabout future endogenous variables after new policies
7
Level-k Thinking
Game Theory
I Stahl-Wilson (1994,1995); Nagel (1995); Crawford (2013)
I Idea: Agents know the game; rationally respond to beliefs;form beliefs about opponents actions recursively
I Result: Level-k thinking better approximates experimentalresults in strategic games (more so in new games)
Macro
I Evans-Ramey; GarciaSchmidt-Woodford; Farhi-Werning
I Idea: Agents know the model; optimize; form expectationsabout future endogenous variables recursively
I Result: Level-k thinking dampens changes in expectationsabout future endogenous variables after new policies
7
Simple Model
Infinitely-lived households solve
max{xt+1,bt+1,ct}
E0
[−1
γ
∞∑t=0
e−ρt−γct
],
subject to
ct + bt+1 + qtxt+1 ≤Wt − Tt + (1 + r)bt + (Dt + qt)xt
need to forecast
(i) Asset returns (asset prices)
(ii) Human capital (taxes)
8
Government
1. Central bank
I announces path {Xt+1, Rt+1} s.t.
Rt+1 = qtXt+1
I transfers profits/losses to the treasury
Trt = (Dt + qt − (1 + r)qt−1)Xt
2. Treasury
I chooses path {Tt, Bt+1} so as to satisfy
(1 + r)Bt = Bt+1 + Trt + Tt
9
Government
1. Central bank
I announces path {Xt+1, Rt+1} s.t.
Rt+1 = qtXt+1
I transfers profits/losses to the treasury
Trt = (Dt + qt − (1 + r)qt−1)Xt
2. Treasury
I chooses path {Tt, Bt+1} so as to satisfy
(1 + r)Bt = Bt+1 + Trt + Tt
9
Asset demand
Assumptions
I Households understand treasury’s BC,
(but may fail to forecast transfers)
I Beliefs about (relevant) future endogenous variables:
ys+1 = αy,s + βy,sεxs+1, y ∈ {q, Tr}
Risky-asset demand
x(qt; {qt+s, T rt+s}) =Et (Dt+1 + qt+1)− (1 + r)qt
γ r1+rσ
2x
− βTr,t
10
Asset demand
Assumptions
I Households understand treasury’s BC,
(but may fail to forecast transfers)
I Beliefs about (relevant) future endogenous variables:
ys+1 = αy,s + βy,sεxs+1, y ∈ {q, Tr}
Risky-asset demand
x(qt; {qt+s, T rt+s}) =Et (Dt+1 + qt+1)− (1 + r)qt
γ r1+rσ
2x
− βTr,t
10
Temporary Equilibrium (TE)
Idea: TE takes as given a sequence of beliefs and imposes thatmarkets clear in every period (Hicks; Lindahl; Grandmont)
Definition Given agents’ beliefs, a TE is{Xt+1, Rt+1, T rt, , Bt+1, Tt; qt; bt+1, xt+1, ct} s.t. {xt+1, bt+1, ct}are optimal, Rt+1 = qtXt+1, the treasury’s BC is satisfied,
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1,
andTrt = (Dt + qt − (1 + r)qt−1)Xt.
REE
11
Temporary Equilibrium (TE)
Idea: TE takes as given a sequence of beliefs and imposes thatmarkets clear in every period (Hicks; Lindahl; Grandmont)
Definition Given agents’ beliefs, a TE is{Xt+1, Rt+1, T rt, , Bt+1, Tt; qt; bt+1, xt+1, ct} s.t. {xt+1, bt+1, ct}are optimal, Rt+1 = qtXt+1, the treasury’s BC is satisfied,
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1,
andTrt = (Dt + qt − (1 + r)qt−1)Xt.
REE
11
Level-k thinking Belief Formation
Status quo {qt+s, T rt+s} = {q∗, 0} (REE before intervention)
Level-1Thinking
x(q1t ; {q∗, 0}) = X −Xt+1
Tr1t =(Dt + q1t − (1 + r)q1t−1
)Xt
}⇒ {q1t , T r1t }
Level-2Thinking
x(q2t ; {q1t+s, T r1t+s}) = X −Xt+1
Tr2t =(Dt + q2t − (1 + r)q2t−1
)Xt
}⇒ {q2t , T r2t }
Level-kThinking
{qkt , T rkt } = Ψ({qk−1t , T rk−1t }; {Xt+1})
REE {qt, T rt} = Ψ({qt, T rt}; {Xt+1})
12
Level-k thinking Belief Formation
Status quo {qt+s, T rt+s} = {q∗, 0} (REE before intervention)
Level-1Thinking
x(q1t ; {q∗, 0}) = X −Xt+1
Tr1t =(Dt + q1t − (1 + r)q1t−1
)Xt
}⇒ {q1t , T r1t }
Level-2Thinking
x(q2t ; {q1t+s, T r1t+s}) = X −Xt+1
Tr2t =(Dt + q2t − (1 + r)q2t−1
)Xt
}⇒ {q2t , T r2t }
Level-kThinking
{qkt , T rkt } = Ψ({qk−1t , T rk−1t }; {Xt+1})
REE {qt, T rt} = Ψ({qt, T rt}; {Xt+1})
12
Level-k thinking Belief Formation
Status quo {qt+s, T rt+s} = {q∗, 0} (REE before intervention)
Level-1Thinking
x(q1t ; {q∗, 0}) = X −Xt+1
Tr1t =(Dt + q1t − (1 + r)q1t−1
)Xt
}⇒ {q1t , T r1t }
Level-2Thinking
x(q2t ; {q1t+s, T r1t+s}) = X −Xt+1
Tr2t =(Dt + q2t − (1 + r)q2t−1
)Xt
}⇒ {q2t , T r2t }
Level-kThinking
{qkt , T rkt } = Ψ({qk−1t , T rk−1t }; {Xt+1})
REE {qt, T rt} = Ψ({qt, T rt}; {Xt+1})
12
Level-k thinking Belief Formation
Status quo {qt+s, T rt+s} = {q∗, 0} (REE before intervention)
Level-1Thinking
x(q1t ; {q∗, 0}) = X −Xt+1
Tr1t =(Dt + q1t − (1 + r)q1t−1
)Xt
}⇒ {q1t , T r1t }
Level-2Thinking
x(q2t ; {q1t+s, T r1t+s}) = X −Xt+1
Tr2t =(Dt + q2t − (1 + r)q2t−1
)Xt
}⇒ {q2t , T r2t }
Level-kThinking
{qkt , T rkt } = Ψ({qk−1t , T rk−1t }; {Xt+1})
REE {qt, T rt} = Ψ({qt, T rt}; {Xt+1})
12
Level-k thinking Belief Formation
Status quo {qt+s, T rt+s} = {q∗, 0} (REE before intervention)
Level-1Thinking
x(q1t ; {q∗, 0}) = X −Xt+1
Tr1t =(Dt + q1t − (1 + r)q1t−1
)Xt
}⇒ {q1t , T r1t }
Level-2Thinking
x(q2t ; {q1t+s, T r1t+s}) = X −Xt+1
Tr2t =(Dt + q2t − (1 + r)q2t−1
)Xt
}⇒ {q2t , T r2t }
Level-kThinking
{qkt , T rkt } = Ψ({qk−1t , T rk−1t }; {Xt+1})
REE {qt, T rt} = Ψ({qt, T rt}; {Xt+1})
12
Level-k thinking Belief Formation
qkt =
D + q∗ − γ r
1+rσ2x
(X −Xt+1
)1 + r
, k = 1
D + qk−1t+1 − γ r1+rσ
2xX
1 + r, k > 1
13
Forward Iteration
Pricing equation (REE)
qt =D + Etqt+1 − γ r
1+rσ2xX
1 + r
Forward Iteration
t4 50 1 2 3
Constant solution
qt =D − γ r
1+rσ2xX
r≡ q∗
14
Forward Iteration
Pricing equation (REE)
qt =D + Etqt+1 − γ r
1+rσ2xX
1 + r
Forward Iteration
t4 50 1 2 3
Constant solution
qt =D − γ r
1+rσ2xX
r≡ q∗
14
Diagonal Iteration
qkt =D + qk−1t+1 − γ r
1+rσ2xX
1 + r,
q1t+k−1 =D + q∗ − γ r
1+rσ2x
(X −Xt+k
)1 + r
t
k
4 50 1 2 31
2
3
4
5
6
Endogenous discounting
15
Diagonal Iteration
qkt =D + qk−1t+1 − γ r
1+rσ2xX
1 + r,
q1t+k−1 =D + q∗ − γ r
1+rσ2x
(X −Xt+k
)1 + r
t
k
4 50 1 2 31
2
3
4
5
6
Endogenous discounting15
Reflective Equilibrium
Idea: agents form beliefs according to level-k thinking, theeconomy is populated by agents with different k with pdf f(k)(Woodford;GarciaSchmidt-Woodford)
In case of exponential f(k) with average k
qt = q∗ + γσ2xr
1 + r·
∑∞k=1
(k−1k
)k−1 Xt+k
(1+r)k
k
Higher k
1. reduces the direct effect of interventions
2. makes the price react more to expected future interventions
Numerical Illustration
16
Reflective Equilibrium
Idea: agents form beliefs according to level-k thinking, theeconomy is populated by agents with different k with pdf f(k)(Woodford;GarciaSchmidt-Woodford)
In case of exponential f(k) with average k
qt = q∗ + γσ2xr
1 + r·
∑∞k=1
(k−1k
)k−1 Xt+k
(1+r)k
k
Higher k
1. reduces the direct effect of interventions
2. makes the price react more to expected future interventions
Numerical Illustration
16
Does QE Affect Output?
Simple Model
I Endowment economy
I Balance sheet policies affect prices and taxes only
An extension
I Output is endogenous (“demand determined”)
I Prices are perfectly rigid (avoids Phillips curve)
I Inelastic supply of safe bonds (but r is still fixed)
I Risky assets are claims on traded part of output
17
Does QE Affect Output?
Simple Model
I Endowment economy
I Balance sheet policies affect prices and taxes only
An extension
I Output is endogenous (“demand determined”)
I Prices are perfectly rigid (avoids Phillips curve)
I Inelastic supply of safe bonds (but r is still fixed)
I Risky assets are claims on traded part of output
17
A Model with Endogenous Output
Households
max{xt+1,bt+1,ct}
E0
[−1
γ
∞∑t=0
eεxt−ρt−γct
]s.t.: ct + bt+1 + qtxt+1 ≤Wt − Tt + (1 + r)bt + (Dt + qt)xt
Total Income/Output Yt distributed as
I Wt = (1− δ)Yt – labor (non-traded) income
I DtX = δYt – dividends
What determines output? goods market clearing (in TE)
Yt = C[Wt(Yt)− Tt(Yt), Dt(Yt), qt, {W e
t+s − T et+s, Det+s, q
et+s}
]
18
A Model with Endogenous Output
Households
max{xt+1,bt+1,ct}
E0
[−1
γ
∞∑t=0
eεxt−ρt−γct
]s.t.: ct + bt+1 + qtxt+1 ≤Wt − Tt + (1 + r)bt + (Dt + qt)xt
Total Income/Output Yt distributed as
I Wt = (1− δ)Yt – labor (non-traded) income
I DtX = δYt – dividends
What determines output? goods market clearing (in TE)
Yt = C[Wt(Yt)− Tt(Yt), Dt(Yt), qt, {W e
t+s − T et+s, Det+s, q
et+s}
]
18
A Model with Endogenous Output
Households
max{xt+1,bt+1,ct}
E0
[−1
γ
∞∑t=0
eεxt−ρt−γct
]s.t.: ct + bt+1 + qtxt+1 ≤Wt − Tt + (1 + r)bt + (Dt + qt)xt
Total Income/Output Yt distributed as
I Wt = (1− δ)Yt – labor (non-traded) income
I DtX = δYt – dividends
What determines output? goods market clearing (in TE)
Yt = C[Wt(Yt)− Tt(Yt), Dt(Yt), qt, {W e
t+s − T et+s, Det+s, q
et+s}
]18
Does QE Affect Output?
Rational expectations equilibrium (no effect of interventions)
q∗ =1
r· δX
(Y − σ2x
γ
)Y ∗t = Y − 1
γεxt
Level-1 equilibrium
q1t − q∗ = ΓqXt+1
X; Y 1
t − Y ∗t = ΓY
(Xt+1
X
)2
Level-k equilibrium
qkt − q∗ =1
1 + r
δ
X(Y k−1t+1 − Y
∗t+1) +
1
1 + r(qk−1t+1 − q
∗)
Y kt − Y ∗t =
∞∑j=1
1
(1 + r)j
[Ψ1(Y
k−1t+j − Y
∗t+j) + Ψ2(q
k−1t+j − q
kt+j)
2]
19
Does QE Affect Output?
Rational expectations equilibrium (no effect of interventions)
q∗ =1
r· δX
(Y − σ2x
γ
)Y ∗t = Y − 1
γεxt
Level-1 equilibrium
q1t − q∗ = ΓqXt+1
X; Y 1
t − Y ∗t = ΓY
(Xt+1
X
)2
Level-k equilibrium
qkt − q∗ =1
1 + r
δ
X(Y k−1t+1 − Y
∗t+1) +
1
1 + r(qk−1t+1 − q
∗)
Y kt − Y ∗t =
∞∑j=1
1
(1 + r)j
[Ψ1(Y
k−1t+j − Y
∗t+j) + Ψ2(q
k−1t+j − q
kt+j)
2]
19
Does QE affect output?
Result
I First-order effect on asset prices
I Second-order effect on output
Intuition
I Higher asset prices lead to first-order wealth effect
I Offset by higher borrowing by the CB
I Only effect is to reduce perceived risk
I Less precautionary saving, more consumption/output(second order)
20
Extensions
1. Foreign exchange interventions (+nominal variables) Details
2. Long-term public bonds purchases (+nominal variables)
I Model with level-1 thinkers resembles Vayanos-Vila (2009)
3. Learning to play equilibrium Details
I Existing policy effect disappears over timeI New policies are less effective
4. Limited participation + level-k thinking
I Negative interaction
5. Presence of rational expectations agents Details
I Does not change qualitative resultsI Can amplify effects due to level-k thinking
21
Testable Predictions
Forecast errors
I Agents make predictable forecast errors
I The errors can differentiate the model from other theories(segmented markets, signaling channel)
Forecast errors in the data
I Forecasts of future taxes?
I Forecasts of asset prices
Forecast errors in the model
Individual: ukt+s ≡ qt+s − Ekt qt+s
Average: ut+s ≡∞∑k=1
f(k)ukt+s = µsγσ2x
r1+rXt+1
k[(1 + r − µ)k + µ]
22
Testable Predictions
Forecast errors
I Agents make predictable forecast errors
I The errors can differentiate the model from other theories(segmented markets, signaling channel)
Forecast errors in the data
I Forecasts of future taxes?
I Forecasts of asset prices
Forecast errors in the model
Individual: ukt+s ≡ qt+s − Ekt qt+s
Average: ut+s ≡∞∑k=1
f(k)ukt+s = µsγσ2x
r1+rXt+1
k[(1 + r − µ)k + µ]
22
Testable Predictions
Forecast errors
I Agents make predictable forecast errors
I The errors can differentiate the model from other theories(segmented markets, signaling channel)
Forecast errors in the data
I Forecasts of future taxes?
I Forecasts of asset prices
Forecast errors in the model
Individual: ukt+s ≡ qt+s − Ekt qt+s
Average: ut+s ≡∞∑k=1
f(k)ukt+s = µsγσ2x
r1+rXt+1
k[(1 + r − µ)k + µ]
22
Empirics
Fieldhouse-Mertens-Ravn (2018, QJE)
I Monthly data on GSEs mortgage purchases: 1967-2006
I “Unexpected exogenous” purchases narrative identification
I Result: mortgage yield reacts significantly to interventions
Forecast errors
I Blue Chip conventional mortgage rate forecasts: 1982-2006
I Project median forecast errors on “exogenous” purchases
23
Fieldhouse-Mertens-Ravn (2018)
1st stage ∑hj=0 pt+j
Xt= αh + γh
mt
Xt+ ϕh(L)Zt−1 + ut+h
I pt – policy action (agency commitments)
I mt – a noncyclical narrative policy indicator
I Xt – a deterministic trend in real personal income
2nd stage
yt+h − yt−1 = αh + γh
(12
8×∑7
j=0 pt+j
Xt
)︸ ︷︷ ︸
≡QEt
+ ϕh (L)Zt−1 + ut+h
24
Forecast Errors
Forecasts Etrt+h
m m+1 m+2
Q Q+1 Q+2
t
Forecast errorut,t+h = rt+h − Etrt+h
H0: ut,t+h is uncorrelated with QEt−1
25
Forecast Errors
Forecasts Etrt+h
m m+1 m+2
Q Q+1 Q+2
t
Forecast errorut,t+h = rt+h − Etrt+h
H0: ut,t+h is uncorrelated with QEt−1
25
Forecast Errors
Forecasts Etrt+h
m m+1 m+2
Q Q+1 Q+2
t
Forecast errorut,t+h = rt+h − Etrt+h
H0: ut,t+h is uncorrelated with QEt−1
25
Forecast Errors
Blue Chip Financial Forecasts (BCFF)
m m+1 m+2
Q Q+1 Q+2
t
BCFF next calendar quarter forecast error
ut,t+“1:3” =
∑2i=0 rt+3+i−mod(t+2,3)
3− f“1:3”t
H0: ut,t+“3(k−1)+1:3k” is uncorrelated with QEt−1
26
Forecast Errors
Blue Chip Financial Forecasts (BCFF)
m m+1 m+2
Q Q+1 Q+2
t
BCFF next calendar quarter forecast error
ut,t+“1:3” =
∑2i=0 rt+3+i−mod(t+2,3)
3− f“1:3”t
H0: ut,t+“3(k−1)+1:3k” is uncorrelated with QEt−126
0 6 12 18 24h (months)
-20
-15
-10
-5
0
5
basi
s po
ints
27
1-3 4-6 7-9 9-12h (months)
-15
-10
-5
0
basi
s po
ints
28
Conclusion
1. Bounded rationality channel of balance sheet policies
I Level-k thinking belief formation
2. Testable predictions
I Forecast errors respond to interventions
I Evidence from mortgage rate forecasts errors
29
Rational Expectations Equilibrium
Definition: REE is a TE such that
qt = qt, T rt = Trt
Specifically
αTr,t + βTr,tεxt+1︸ ︷︷ ︸
beliefs T rt+1
REE=(D + qt+1 − (1 + r)qt
)Xt+1 +Xt+1ε
xt+1︸ ︷︷ ︸
realized transfers Trt+1
Risky assets market in t
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1
⇒ Balance sheet policy does not affect price qt in REE!Back
30
Rational Expectations Equilibrium
Definition: REE is a TE such that
qt = qt, T rt = Trt
Specifically
αTr,t + βTr,tεxt+1︸ ︷︷ ︸
beliefs T rt+1
REE=(D + qt+1 − (1 + r)qt
)Xt+1 +Xt+1ε
xt+1︸ ︷︷ ︸
realized transfers Trt+1
Risky assets market in t
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1
⇒ Balance sheet policy does not affect price qt in REE!Back
30
Rational Expectations Equilibrium
Definition: REE is a TE such that
qt = qt, T rt = Trt
Specifically
αTr,t + βTr,tεxt+1︸ ︷︷ ︸
beliefs T rt+1
REE=(D + qt+1 − (1 + r)qt
)Xt+1 +Xt+1ε
xt+1︸ ︷︷ ︸
realized transfers Trt+1
Risky assets market in t
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1
⇒ Balance sheet policy does not affect price qt in REE!Back
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Rational Expectations Equilibrium
Definition: REE is a TE such that
qt = qt, T rt = Trt
Specifically
αTr,t + βTr,tεxt+1︸ ︷︷ ︸
beliefs T rt+1
REE=(D + qt+1 − (1 + r)qt
)Xt+1 +Xt+1ε
xt+1︸ ︷︷ ︸
realized transfers Trt+1
Risky assets market in t
D + Etqt+1 − (1 + r)qtγ r1+rσ
2x
− βTr,t = X −Xt+1
⇒ Balance sheet policy does not affect price qt in REE!Back
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Numerical Illustration
0 5 10 15 20 25 300
0.005
0.01
0.015
Back
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Open Economy Model
New elements
I 2 countries: Home (size ω), Foreign (size 1− ω)
I Additional assets: riskless nominal bonds (in eachcountry), money (in each country)
I Goods: single traded good (LOOP holds)
I Risk: money supply (=inflation risk)
I Monetary policy: logMt+1 = logM + εht (home)
I FX intervention: {−Bht+1, B
ft+1} (home)
Back
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Solution
Money markets
mt − pt = −vitm∗t − p∗t = −vi∗t
Bond markets
Home: ωbH,t+1 + (1− ω)b∗H,t+1 = −Bht+1
Foreign: ωbF,t+1 + (1− ω)b∗F,t+1 = B∗ −Bft+1
Back
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Nominal Exchange Rate
Rational expectations equilibrium
et =v
1 + vEtet+1 +
1
1 + v(mt −m∗t ) ⇒ eREEt
Reflective equilibrium (summing over different level-k’s)
et = eREEt +γ
(1 + v)2
∞∑k=1
f (k)
(v
1 + v
)k+2 [σ2fB
ft+k + σ2h(−Bh
t+k)]
Back
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Unraveling
Assumption: agents become more sophisticated over time
ft (k) =
{f(k − ht), k ≥ 1 + ht,
0, k < 1 + ht,
When asset purchases follow Xt+1 = µtX1
qt − qREE =γσ2xω· 11+r−µ1−λ + µ
X1
(µ1+h
(1 + r)h
)tBack
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REE Agents
Assumption
I φ agents form expectations rationally
I (1− φ) agents form expectations using level-k thinking
Risky asset price
qt = qREE + (1− φ) γσ2x
∞∑k=1
f(k)
(1 + r)k
∞∑s=0
(φ
1 + r
)sXt+s+k
Risky asset price without REE agents
qt = qREE + γσ2x
∞∑k=1
f(k)
(1 + r)kXt+k
Back
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