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O PTIMAL M ONETARY P OLICY FOR
THE M ASSES
James Bullard (FRB of St. Louis)
Riccardo DiCecio (FRB of St. Louis)

Barcelona GSE, Summer Forum
Workshop on Monetary Policy and Central Banking
Barcelona, Spain
June 14, 2018
Any opinions expressed here are our own and do not necessarily reflect those of the FOMC.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

Introduction

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

I NEQUALITY AND MONETARY POLICY

Interest in income, financial wealth, and consumption inequality
has increased in the last decade.
Can monetary policy conducted in a way that benefits all
households even in a world of substantial heterogeneity?
The answer in this paper is “yes.”

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

S OME RECENT LITERATURE
Conference on “Monetary Policy and the Distribution of Income
and Wealth,” held at the St. Louis Fed on September 11 and 12,
2015. Program available online.
Kaplan, Moll, and Violante (AER, 2018): new Keynesian macro
with uninsurable idiosyncratic risk and multiple assets
(“HANK”). Produces reasonable Gini coefficients. The monetary
transmission mechanism is altered relative to the representative
agent case. Also provides a good discussion of the literature.
This paper also produces reasonable Gini coefficients, and
features incomplete markets due to a friction, with strictly
limited idiosyncratic risk. The policymaker is able to repair the
distortion caused by the friction for all households.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

H OUSEHOLD CREDIT IN A DSGE

I NEQUALITY

P OLICY

C ONCLUSIONS

MODEL

We study an economy with a large private credit market
essential to good macroeconomic performance.
This market has an important friction: Non-state contingent
nominal contracting (NSCNC).
The role of monetary policy will be to keep this large credit
market functioning properly (i.e., complete).
We ignore ZLB issues in this talk. See the companion paper by
Azariadis, Bullard, Singh and Suda (2015).

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

W EALTH , INCOME AND

I NEQUALITY

P OLICY

C ONCLUSIONS

CONSUMPTION INEQUALITY

There is a lot of wealth, income and consumption inequality in
this stylized model.
The role of credit markets, if they work correctly, will be to
re-allocate uneven income profiles across the life cycle into
perfectly equal consumption shares by cohort, appropriately
scaled by life cycle productivity.
The model equilibrium will naturally rank:
wealth Gini > income Gini > consumption Gini.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

T HE MONETARY POLICY IMPLICATIONS

Optimal monetary policy in this model looks like “nominal GDP
targeting”—countercyclical price level movements.
This result continues to hold even when there is “massive”
heterogeneity—enough heterogeneity to approximate income,
financial wealth, and consumption inequality in the U.S.
Hence, the main result is that NGDP targeting constitutes “optimal
monetary policy for the masses” in this environment.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

Environment

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

L IFE CYCLE MODELS

General equilibrium life cycle economy = many-period
overlapping generations.
Key variables are privately-issued debt, real interest rates and
inflation.
Think of privately-issued debt = “mortgage-backed securities.”
There is no government spending or taxes of any kind.

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

S YMMETRY ASSUMPTIONS
We make a set of important “symmetry assumptions.”
These assumptions involve the symmetry of the life cycle
productivity endowment pattern of the households (detailed
below), along with log preferences, no discounting, and no
population growth.
These assumptions help deliver the result that in the equilibria
we study:
The real interest rate is exactly equal to the output growth rate at every
date, even in the stochastic economy.

Could think of this as the Wicksellian natural real rate of interest.
This in turn creates a set of easy to understand baseline results
for this economy.

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

E NVIRONMENT DETAILS
Standard (T + 1)-periods (quarterly) DSGE life-cycle
endowment economy.
Each period, a new cohort of households enters the economy,
makes economic decisions over the next 241 periods, then exits
the economy.
There is one asset in the model, privately-issued debt
(consumption loans).
The monetary authority controls the nominal price level P (t)
directly.
For a money demand version, see Azariadis et al. (2015).

All households have log preferences with no discounting.
Other assumptions: No population growth, no capital, no default,
flexible prices, no borrowing constraints.

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

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C ONCLUSIONS

K EY FRICTION : NSCNC

Loans are dispersed and repaid in the unit of account—that is, in
nominal terms—and are not contingent on income realizations.
There are two aspects to this assumption.
The non-state contingent aspect means that real resources are
misallocated via this friction.
The nominal aspect means that the monetary authority may be able
to fix the distortion.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

L INEAR PRODUCTION TECHNOLOGY
We model a growing economy in which a linear technology is
improving over time.
Aggregate real output Y (t) is given by
Y (t) = Q (t) L (t) ,

(1)

where L (t) is the aggregate labor input and Q (t) is the level of
technology (also TFP and labor productivity).
The level of technology grows at a stochastic rate λ (t, t + 1)
between dates t and t + 1,
Q (t + 1) = λ (t, t + 1) Q (t) ,
where the stochastic process for λ is defined on the next slide.

(2)

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

S TOCHASTIC STRUCTURE

The real wage w (t) is then exogenously given by
w (t + 1) = λ (t, t + 1) w (t) ,

(3)

where w (0) > 0, and λ (t, t + 1) is the gross rate of aggregate
productivity growth between date t and date t + 1, and where
λ (t, t + 1) = (1

ρ) λ̄ + ρλ (t

1, t) + σe (t + 1) ,

(4)

where λ̄ > 1 represents the average gross growth rate, ρ 2 (0, 1) ,
σ > 0, and e (t + 1) is a truncated normal with bounds b, b > 0,
such that the ZLB avoided.

I NTRODUCTION

E NVIRONMENT

T IMING

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

PROTOCOL

At the beginning of date t, nature moves first and chooses
λ (t 1, t) , which implies a value for w(t).
The policymaker moves next and chooses a value for P (t) .
Households then decide how much to work, consume and save.

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

N OMINAL INTEREST RATE CONTRACTS

Households contract by fixing the nominal interest rate one
period in advance.
The non-state contingent nominal interest rate, “the contract
rate,” is given by
Rn (t, t + 1)

1

= Et

ct ( t )
P (t)
.
ct ( t + 1 ) P ( t + 1 )

(5)

This rate can be understood as expected nominal GDP growth.
In the equilibria we study, this expectation is the same for all
households, even those born at different dates or with different
levels of productivity.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

W HAT MONETARY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

POLICY DOES

The countercyclical price level rule delivers complete markets
allocations:
Rn (t 1, t)
P (t) = r
P (t 1) ,
(6)
λ (t 1, t)
where λr indicates a realization of the shock and Rn is the
expectation given in the previous slide—similar to Sheedy
(BPEA, 2014) and Koenig (IJCB, 2013).
Given this policy rule, households consume equal amounts of
available production, given their productivity, “equity share
contracting,” which is optimal under homothetic preferences.
This price level rule renders the households’ date-t decision
problem deterministic because it perfectly insures the household
against future shocks to income.
Consumption and asset holdings fluctuate from period to
period, but in proportion to the value of w (t) .

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

Life-Cycle Productivity

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

L IFE - CYCLE PRODUCTIVITY PROFILES

Households
entering
the economy draw a scaling factor
h
i
1
x U ξ , ξ and receive a life cycle productivity profile which
is a scaled version of the baseline profile, es :
es,i = x es ,
where ξ 1 determines the within-cohort dispersion.
Life cycle productivity profiles are deterministic.
Huggett, Ventura and Yaron (AER, 2011) argue that differences in
initial conditions are more important than differences in shocks.

I NTRODUCTION

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

AVERAGE LIFE - CYCLE PRODUCTIVITY

The baseline profile, es , is given by:
"
es = f (s) = 2 + exp

s

120
60

4

#

.

Profiles begin at a low value, rise to a peak in the middle period
of life, and then decline to the low value.
Life cycle productivity profiles are symmetric.
Agents can sell productivity units available in a particular period
in the labor market at the competitive wage per effective
efficiency unit.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

B ASELINE LIFE - CYCLE PRODUCTIVITY
3.5
3
2.5
2
1.5
0

60

120

180

240

quarters
F IGURE : Baseline endowment profile. The profile is symmetric and peaks in
the middle period of the life cycle.

I NTRODUCTION

E NVIRONMENT

T HE MASS

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

OF LIFE - CYCLE PRODUCTIVITY

F IGURE : The mass of endowment profiles: es,i
es = 2 + exp

I NEQUALITY

s 120
60

4

, ξ = 6.5.

es U ξ

1

,ξ ,

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

S TATIONARY EQUILIBRIA

We let t 2 ( ∞, +∞) .
We only consider stationary equilibria under perfectly credible
policy rules governing P (t) .
We let R (t) be the gross real rate of return in the credit market.
Stationary equilibrium is a sequence fR (t) , P (t)gt+=∞ ∞ such that
markets clear, households solve their optimization problems,
and the policymaker credibly adheres to the stated policy rule.
Key condition is that aggregate asset holding A (t) = 0 8t.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

S TATIONARY EQUILIBRIA

T HEOREM
Assume symmetry as defined above. Assume the monetary authority
credibly uses the price level rule 8t. Then the general equilibrium gross real
interest rate, R (t 1, t) , is equal to the gross rate of aggregate productivity
growth, and hence the real growth rate of the economy, λ (t 1, t) , 8t.

C OROLLARY
For any two households that share the same productivity profile,
consumption is equalized at each date t.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

Characterizing the Equilibrium

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

L ABOR / LEISURE
1
0.8
0.6
0.4
0.2
0

0

60

120

180

240

quarters
F IGURE : Leisure decisions by age (green), labor supply by age (blue) and
fraction of work time in U.S. data, 19% (red). The labor/leisure choice
depends on the current-to-lifetime average productivity ratio. Productivity
profiles of the form es,i = x es imply labor/leisure choices dependent on age
only.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

L ABOR INCOME MASS

F IGURE : Labor income profiles es,i (1

`) w; ξ = 6.5, η = 0.21, and w = 1.

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

C ONSUMPTION MASS

F IGURE : Consumption mass (red) and labor income mass (blue) along the
complete markets balanced growth path with w (t) = 1. Under optimal
monetary policy, the private credit market reallocates uneven labor income
into perfectly equal consumption for each productivity profile. The
consumption Gini is 31.8%, similar to values calculated from U.S. data.

I NTRODUCTION

E NVIRONMENT

N ET

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

ASSET HOLDING MASS

F IGURE : Net asset holding mass by cohort along the complete markets
balanced growth path. Borrowing, the negative values to the left, peaks at
stage 60 of the life cycle (age ~35), while positive assets peak at stage of life
180 (age ~65). The financial wealth Gini is 72.7%, similar to values calculated
in U.S. data.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

T HREE NOTIONS

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

OF INCOME

Three notions of income:
1

Labor income,
Y1 = es,i [1

2

`t (t + s)] w (t + s) ,

Labor income plus non-negative capital income,
Y2 = es,i [1

`t (t + s)] w (t + s) +
+ max [λ (t + s, t + s

3

1)

1]

at,i (t + s 1)
,0 ,
P (t + s 1)

The non-negative component of total income,
)
(
es,i [1 `t (t + s)] w (t + s) +
Y3 = max
.
a (t+s 1)
+ [λ (t + s, t + s 1) 1] Pt,i(t+s 1) , 0

Gini coefficients of income distributions: GY1 = 56.2%,
GY2 = 51.6%, GY3 = 59.6%.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

L ABOR INCOME + NON - NEGATIVE CAPITAL INCOME

F IGURE : Profiles of labor income and non-negative capital income
es,i (1 `) w + max (λ 1) Pa , 0 ; ξ = 6.5, η = 0.21, and w = 1.

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

N ON - NEGATIVE TOTAL INCOME

F IGURE : Profiles of non-negative total income
max es,i (1 `) w + (λ 1) Pa , 0 ; ξ = 6.5, η = 0.21, and w = 1.

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

Inequality

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

D ENSITIES
En dowm e n t

0.1

1

0.05
0

Labor in com e

0.5
0

0

10

0

C on su m pti on

W e alth

0.02

0.5

5

0.01
0

0

2

0

0

100

F IGURE : PDFs of endowment, labor income, consumption and wealth. Note:
the wealth subplot omits a mass point (121/241) at 0.

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C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

D ATA ON INEQUALITY IN THE U.S.

Consumption (Heathcote, Perri and Violante, RED, 2010):
GC,U.S. = 32%.
Income (CBO, 2016): pre-taxes/transfers GY,U.S. = 51%;
post-taxes/transfers GY,U.S. = 43%.
Financial wealth (Davies, Sandström, Shorrocks and Wolff, EJ,
2011): GW,U.S. = 80%.

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

I NEQUALITY IN THE MODEL
Large amount of heterogeneity which depends in part on life
cycle productivity dispersion.
Financial wealth is defined as the non-negative part of net assets.
Denote GW , GY , and GC as the financial wealth, income, and
consumption Gini coefficients, respectively, in the model.
For ξ = 6.5 and η = 0.21
GW = 72.7% > GY2 = 51.6% > GC = 31.8%,
versus U.S. data
GW,U.S. = 80% > GY,U.S. = 51% > GC,U.S. = 32%.

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

P RODUCTIVITY DISPERSION AND G INI COEFFICIENTS
1
0.8
0.6
0.4
Wealth
Labor income
Consumption

0.2
0

2

4

6

8

10

F IGURE : As the dispersion of productivity profiles, ξ, increases, the Gini
coefficients increase. The ordering GW > GY > GC is preserved.

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

Policy

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NTERPRETING MONETARY

I NEQUALITY

P OLICY

POLICY

The price level rule characterizes policy by “counter cyclical
price level” movements.
But the policy can also be interpreted more conventionally in
interest rate terms.
Contracts are made understanding policy ...
And policy is made understanding contracts ...
Interest rate policy is a fixed point of this process.

C ONCLUSIONS

I NTRODUCTION

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P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

P OLICY CHARACTERIZATION

The contract nominal rate is the expected rate of nominal GDP
growth.
Wicksellian natural real rate = λ.
The contract nominal rate is always ratified ex post.
This makes the real rate = λ.
“Just like the simple NK model.”

I NTRODUCTION

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P RODUCTIVITY

N OMINAL GDP

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

TARGETING

Suppose ρ = 0 : Then the expected rate of NGDP growth never
changes, and the economy never deviates from the NGDP path.
“Perfect NGDP targeting.”
Suppose ρ > 0 : Then the expected rate of NGDP fluctuates
persistently with the shock, and it takes longer to return to the
NGDP path.
Nominal and real rates fall in a recession.

I NTRODUCTION

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E FFECTS

P RODUCTIVITY

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

OF A SHOCK
1.06
1.02
1.04
1
1.02
0

5

10

0

quarters

5

10

quarters

1.4

1.06
1.04

1.2

1.02
1
0

5

quarters

10

0

5

10

quarters

F IGURE : Monetary policy responds to a decrease in aggregate productivity,
λ, by increasing the price level in the period of the shock. Subsequently,
inflation converges to its BGP value, π , from below. The nominal interest
rate drops in the period after the shock.

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C HARACTERIZING THE E QUILIBRIUM

Conclusions

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

A LL HOUSEHOLDS

C HARACTERIZING THE E QUILIBRIUM

I NEQUALITY

P OLICY

C ONCLUSIONS

FACE A CONSUMPTION SMOOTHING

PROBLEM

This paper attributes observed levels of U.S. inequality to
life-cycle effects in conjunction with heterogeneous life-cycle
productivity profiles.
All households in this model, regardless of their assigned
life-cycle productivity profile, face a problem of smoothing
life-cycle consumption in a world with a NSCNC friction.
The monetary authority can remove this impediment to life-cycle
consumption smoothing for all households.