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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)

Swiss National Bank Research Conference 2018
Current Monetary Policy Challenges
Zurich, Switzerland
Sept. 21, 2018
Any opinions expressed here are our own and do not necessarily reflect those of the FOMC.

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

E QUILIBRIUM

Introduction

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

E NVIRONMENT

P RODUCTIVITY

E QUILIBRIUM

I NEQUALITY

P OLICY

I NEQUALITY AND MONETARY POLICY

Can monetary policy be conducted in a way that benefits all
households even in a world of substantial heterogeneity?
The answer in this paper is “yes.”

C ONCLUSIONS

I NTRODUCTION

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C ONCLUSIONS

S OME RECENT LITERATURE
Kaplan, Moll, and Violante (AER, 2018):
NK macro with heterogeneous households (“HANK”); reasonable
Gini coefficients.
The monetary policy transmission mechanism is substantially
altered relative to standard model.

Bhandari, Evans, Golosov, and Sargent (Working paper, NYU,
2018):
Incomplete markets, nominal friction, heterogeneous households
(“HAIM”); reasonable Gini coefficients.
Optimal monetary-fiscal policy (Ramsey) substantially altered
relative to standard model.
See A. Bhandari, D. Evans, M. Golosov, and T. Sargent, "Inequality,
Business Cycles, and Monetary-Fiscal Policy," Working Paper, New
York University, June 6, 2018, available at
http://www.tomsargent.com/research/begs2.pdf.

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S OME RECENT LITERATURE

Bullard and DiCecio (Working paper, St. Louis Fed, 2018):
Incomplete markets, nominal friction, heterogeneous households
(“HAIM”); reasonable Gini coefficients.
Optimal monetary policy repairs the distortion caused by the
friction for all households.

See also the conference on “Monetary Policy and the Distribution
of Income and Wealth,” held at the St. Louis Fed on Sept. 11–12,
2015. Program available at https://research.stlouisfed.org/
conferences/monetary_policy_conf/program.

I NTRODUCTION

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P RODUCTIVITY

W EALTH , INCOME AND

E QUILIBRIUM

I NEQUALITY

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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, is to reallocate
uneven income profiles across the life cycle into equal
consumption shares by cohort, appropriately scaled by life-cycle
productivity.
The model equilibrium features reasonable Gini coefficients.

I NTRODUCTION

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C ONCLUSIONS

T HE MONETARY POLICY IMPLICATIONS

The role of monetary policy in this model is to make sure private
credit markets are working correctly (i.e., complete).
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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Environment

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C ONCLUSIONS

I NTRODUCTION

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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 nor are there taxes of any kind.

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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.

We can 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.

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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 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.

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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)

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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

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T IMING

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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.

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N OMINAL INTEREST RATE CONTRACTS
Households meet in a large competitive credit market.
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.

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W HAT MONETARY

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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

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I NEQUALITY

Life-Cycle Productivity

P OLICY

C ONCLUSIONS

I NTRODUCTION

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C ONCLUSIONS

L IFE - CYCLE PRODUCTIVITY PROFILES

Households
entering
the economy draw a scaling factor
h
i
x U ξ 1 , 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.
This process means all idiosyncratic risk is borne by agents at the
beginning of the life cycle.
Huggett, Ventura and Yaron (AER, 2011) argue that differences in
initial conditions are more important than differences in shocks.

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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.
Once assigned, profiles do not change.
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.

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C ONCLUSIONS

B ASELINE LIFE - CYCLE PRODUCTIVITY
4

3

2

1

0
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

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T HE MASS

P RODUCTIVITY

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P OLICY

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 ,

C ONCLUSIONS

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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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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.

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P OLICY

Characterizing the Equilibrium

C ONCLUSIONS

I NTRODUCTION

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C ONCLUSIONS

L ABOR / LEISURE
1

0.5

0
0

60

120

180

240

quarters
F IGURE : Leisure decisions (green), labor supply (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.

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L ABOR INCOME MASS

F IGURE : Labor income profiles es,i (1

`) w; ξ = 6.5, η = 0.21, and w = 1.

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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

N ET

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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.

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T HREE NOTIONS

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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%.

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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

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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

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P RODUCTIVITY

E QUILIBRIUM

Inequality

I NEQUALITY

P OLICY

C ONCLUSIONS

I NTRODUCTION

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P RODUCTIVITY

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C ONCLUSIONS

D ENSITIES

Endowment

0.1
0.05

Labor income

1
0.5

0

0
0

10

Consumption
0.5

0
0.02

5

Wealth

0.01
0

0
0

2

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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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

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C ONCLUSIONS

I NEQUALITY IN THE MODEL

Large amount of heterogeneity that depends in part on life-cycle
productivity dispersion.
Financial wealth is defined as the non-negative part of net assets.
We also consider lognormal productivity, ln (x) N µ, σ2 :
Allows for arbitrarily rich and arbitrarily poor households.
All distributions (wealth, income and consumption) are mixtures
of lognormals (and δ functions).
Gini coefficients can be computed with “paper and pencil.”

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G INI COEFFICIENTS

Wealth
W

Y1

Income
Y2

Y3

51%

Consumption
C

U.S. data

80%

32%

Uniform

72.7%

56.2%

51.6%

59.6%

31.8%

Lognormal

72.4%

55.7%

51.1%

59.0%

32%

TABLE : Gini coefficients in the U.S. data and in the model with uniform and
lognormal productivity.

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P RODUCTIVITY DISPERSION AND G INI COEFFICIENTS

Wealth
Labor income
Consumption

1

0.5

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

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Policy

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P OLICY

C ONCLUSIONS

I NTRODUCTION

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P RODUCTIVITY

I NTERPRETING MONETARY

E QUILIBRIUM

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C ONCLUSIONS

POLICY

The price level rule characterizes policy by “countercyclical 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.

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P OLICY CHARACTERIZATION

The nominal rate is determined one period in advance as the
expected rate of nominal GDP growth.
Wicksellian natural real rate = aggregate productivity growth
rate, λ.
The nominal rate is always ratified ex post by the policymaker.
This makes the real rate = aggregate productivity growth rate =
Wicksellian natural real rate of interest.
“Just like the simple NK model.”

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N OMINAL GDP

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C ONCLUSIONS

TARGETING

How can we interpret these results as NGDP targeting?
No persistence in productivity growth, ρ = 0: The expected rate of
NGDP growth never changes, and the economy never deviates
from the NGDP path. “Perfect NGDP targeting.”
Persistence in productivity growth, ρ > 0: The expected rate of
NGDP growth fluctuates persistently with the shock, and it takes
longer to return to the balanced growth NGDP path.
Nominal and real rates fall in a recession.

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E FFECTS

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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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Conclusions

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S UMMARY
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 credit market friction,
“non-state contingent nominal contracting.”
The monetary authority can remove this impediment to life-cycle
consumption smoothing for all households: “optimal monetary
policy for the masses.”
Does monetary policy affect inequality? Yes, it improves
consumption allocations, alters the asset holding distribution,
and alters the income distribution by altering hours worked.