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Home / Publications / Research / Economic Brief / 2024

Can China Avoid a Liquidity-Trap Recession? Some
Unintended Consequences of Macroprudential Policies
By Russell Wong

Economic Brief
April 2024, No. 24-12

E orts to avoid a liquidity trap could ultimately cause one to happen. In this
article, I examine how this occurs, what implications such actions have for
other macroeconomic policies and what else can be done to avoid liquidity
traps.
In Shakespeare's famous tragedy, Macbeth acknowledged his biggest threats and was
determined to do whatever it took to prevent them. Fueled by ambition and
overcon dence, he was ultimately trapped in a self-ful lling tragedy: T he draconian
measures he used to avoid the downfall he feared only realized his downfall sooner. Like
Macbeth, sometimes policymakers imposing heavy-handed measures to prevent a liquidity
trap might nd themselves in a similar self-ful lling tragedy.
A liquidity trap is a recession featuring excessive savings such that the nominal interest
rate of saving drops to its e ective lower bound, which is typically zero. (If it were lower,
people could hold cash instead to avoid negative nominal interest rates.) It features a spiral
of de ationary pressure and economic slacks like high unemployment rates and GDP far
below its potential, as seen in the Great Depression in the 1930s and the Great Recession
in 2008.
A liquidity trap is a nightmare for central banks because the zero lower bound constrains
them from further reducing the nominal interest rate to stimulate the economy. T he
nightmare can be long: For example, Japan — formerly the world's second-largest economy
after the U.S. — has been battling its liquidity trap since its real-estate bubble burst in
1990. Recently, some commentators have argued that a liquidity trap is imminent in China
— currently the world's second-largest economy — pointing to signs such as deposit surge
(despite declining interest rates), mounting de ationary pressures and high
unemployment rates among youth.
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Avoiding Liquidity Traps
It is now widely accepted that a better way to ght a liquidity trap is to avoid it, which is the
idea behind many macroprudential policies nowadays. For example, China has recently
introduced various macroprudential policies — the so-called "three red lines" — to its real
estate sector, bearing Japan's lessons in mind.1
But how does a liquidity trap happen in the rst place? We need to understand its
mechanism to defuse it. In a traditional Keynesian analysis, a liquidity trap happens when
the downward sloping investment-saving (IS) curve cuts the at portion of the liquidity
preference-money supply (LM) curve.
However, this account of a liquidity trap is found unsatisfactory in explaining Japan's
balance-sheet recession in 1990 and the U.S.'s Great Recession in 2008. As pointed out by
economist Richard Koo, the massive deleveraging of heavily indebted rms and households
had a clear role in these two famous liquidity traps (and possibly even in China) but was not
so clear in the IS-LM theory. Recent academic research has explicitly analyzed the role of
deleveraging in a liquidity trap and its implication on policy.2 In this article, I analyze the
e ect of a leverage regulation that aims to prevent a liquidity trap, based on my recent
research. All the derivation can be found in the footnotes.
T o analyze the consequences of (de)leveraging, consider the situation of borrowers and
savers in an economy. Borrowers are typically rms, local governments or leveraged
investors (such as those invested in real estate) that rely on rolling over previous debt
(denoted as d0) to continue their operations. Savers are typically households and investors
who decide how much of today's income to save (denoted as dS) to earn the interest rate r
for tomorrow's consumption.
As in standard economic analysis, savers choose the level of saving such that their
intertemporal marginal rate of substitution (MRS) between today's consumption and
tomorrow's consumption equals the interest rate, denoted as MRSS(dS)=r. T he MRS
measures the marginal utility of today's consumption against the marginal utility of
tomorrow's consumption (that is, the amount of tomorrow's consumption needed to gain
per unit of today's consumption forgone to keep the total savers' utility unchanged).3
Since the saver's MRS is increasing in the level of saving, it constitutes an upward sloping
supply curve in the debt market, as illustrated in Figure 1.

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Enlarge
Similarly, the borrowers decide how much of their debt today (denoted as dB) is rolled over
to maintain today's consumption, which costs them interest and reduces tomorrow's
consumption. Again, the borrowers choose the level of borrowing such that their MRS
equals the interest rate, denoted as MRSB(dB)=r.4 Since the borrower's MRS is decreasing
in the level of borrowing, it constitutes a downward sloping demand curve in the debt
market.
In equilibrium, borrowing equals saving equals the aggregate level of debt (dB=dS=d) such
that the debt market clears today, as illustrated in Figure 1. Of course, the same process
will repeat tomorrow and so on. In the steady state, the interest rate equals the agent's
rate of time preference, and the borrowers' debt will be rolled over inde nitely (shown as
d=d0 in Figure 1).5
Now, suppose an excessive aggregate level of debt also exposes the economy to the risk
of a liquidity trap tomorrow. When a liquidity trap happens, the nominal interest rate falls
to the zero lower bound, and output falls below its potential. Since my focus is the
policymaker's response to excessive debt today (and ultimately the liquidity trap
tomorrow), I leave out the details of how the probability of a liquidity trap is determined.
What is important is that the likelihood of a liquidity trap tomorrow is zero when the
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aggregate level of debt today is below some threshold (i.e., d≤θ). Otherwise, it is increasing
in the aggregate level of debt. A relevant case is when borrowers are heavily indebted such
that the inherited debt is greater than the threshold (that is, d0>θ).
T o eliminate the liquidity trap tomorrow, policymakers impose a leverage regulation on
borrowers today: T heir choice of debt cannot exceed some debt limit d‾ in any period (that
is, dB≤d‾) where d‾ ≤ θ. Since borrowers have inherited excessive debt (d0> θ), the leverage
regulation forces them to deleverage today, following the premise that dB≤d‾≤θ<d0.
T he leverage regulation considered above is found in many macroprudential policies. For
example, Basel III imposes a similar leverage ratio requirement on banks. Regulators
impose leverage regulations on non- nancial rms as well. For example, China recently set
restrictions on giant but highly leveraged real estate developers to stop further unchecked
expansion of debt. T he leverage of these developers has stalled since then.
What will be the consequence of imposing the leverage regulation? One can construct the
new equilibrium as illustrated in Figure 2. In the new equilibrium, the interest rate equals
savers' MRS with their level of saving at the debt limit in every period (that is,
r′=MRSS(d‾)).6 At this interest rate, savers are indi erent to making further savings beyond
the debt limit. On the other hand, borrowers have a higher MRS than this interest rate, so
they want to borrow more but cannot because of the debt limit. As shown in Figure 2, the
debt market under the debt limit clears at the lower interest rate r′. In this case, the
leverage regulation with a low level of d‾ eliminates the risk of a liquidity trap and prevents
output from falling below its potential in the future. A low d‾ is also desirable to provide
some bu ers when θ is uncertain.

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Enlarge
So far, so good, but only if savers' MRS is always above the lower bound associated with
the zero nominal interest rate. Note that the interest rate that clears the debt market is
the real rate (or the nominal interest rate minus the expected in ation rate). For simplicity,
consider that there is no in ation, so the real and nominal interest rates are the same.
(Later, we will consider the general case.) T hus, there is a zero lower bound for the real
interest rate.
What would happen if the leverage regulation is so restrictive that savers' MRS is below
the zero lower bound, as illustrated in Figure 2? T hen, savers' marginal utility of
consumption is much lower today than tomorrow. It could happen when the leverage
regulation forces borrowers to abruptly deleverage their borrowing from d0 to d‾. In
equilibrium, it means savers also abruptly reduce their savings from d0 to d‾ to clear the
debt market. T his dissaving is achieved by a signi cant increase in savers' consumption
today. Since the marginal utility of consumption is decreasing — thanks to the law of
diminishing marginal utility — a higher level of today's consumption implies the marginal
utility of consumption is much lower today than tomorrow (that is, a lower MRS). T hus, a
restrictive leverage regulation featuring a low d‾ can push the interest rate below the zero
lower bound.
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But the interest rate cannot be negative in equilibrium, so something else must be
accommodated to restore the interest rate at the zero lower bound illustrated in Figure 2.
Recall that the aggregate demand for output is the sum of savers' and borrowers'
consumption. In normal times, if aggregate demand is below the potential output Y‾, the
interest rate decreases to push aggregate demand back to the potential level (as savers
save less and borrowers borrow more to consume), and vice versa.
However, if the interest rate at the potential output level is already negative, the interest
rate has to increase until it is restored at the zero lower bound and, hence, the aggregate
demand decreases below the potential output level, as illustrated in Figure 3.

Enlarge
What is the logic behind the aggregate demand curve in Figure 3? Since savers' MRS is now
stuck at zero, it dictates an autonomous level of savers' consumption today, denoted as
CS.7 It is the level of today's consumption required to keep savers' savings at the zero
lower bound.
On the other hand, borrowers' consumption is their income minus paying inherited debt
plus rolling over new debt under the debt limit at the zero lower bound (that is,
CB=Y−d0+d‾). As an illustration, if savers and borrowers share the economy equally, the
aggregate demand for output is simply AD=0.5CB+0.5CS=0.5Y+0.5(CS−d0+d‾).
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In general, aggregate demand will be some weighted average between borrowers' and
consumers' consumption, so aggregate demand is always atter than the 45-degree line.
At the zero-lower-bound equilibrium, aggregate demand equals the output (that is, AD=Y),
cutting the 45-degree line below the potential output level, as illustrated in Figure 3.

Leverage Regulations and Liquidity Traps
T hus, a restrictive leverage regulation designed to eliminate a liquidity trap tomorrow can
lead to a liquidity trap recession today, ful lling a Macbethian tragedy. Figure 4 illustrates
the equilibrium over each regulation and leverage scenario:
Scenario 1: T he leverage regulation can eliminate a liquidity trap in the white corridor
where the inherited leverage is not too high and the leverage regulation is not too
restrictive (moderate debt limit). T he higher the inherited leverage, the narrower the
corridor.
Scenario 2: If the leverage regulation is not restrictive enough (debt limit higher than θ
in the dotted region), then the risk of a liquidity trap is not eliminated.
Scenario 3: If the leverage regulation is too restrictive (the shaded region), the
leverage regulation also induces the economy into a liquidity trap.
Scenario 4: If the economy inherits too much leverage (higher than M), the corridor
disappears, and no leverage regulation can prevent the economy from a liquidity trap
by itself or by regulation.8 A Macbethian tragedy is inevitable in this region.

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Enlarge
A regulation-induced liquidity trap is more devastating (in terms of output) when the
borrowers are more indebted (higher d0) or the leverage regulation is more restrictive
(lower d‾). In these cases, the supply curve in Figure 2 shifts to the right, so a bigger
reduction in output is needed to restore the supply curve at the zero lower bound. T he
multiplier e ect on output by a higher d0 or a lower d‾ is illustrated by shifting the
aggregate demand curve downward in Figure 3.
Note that a lower d‾ has a larger multiplier e ect than a higher d0, as illustrated in Figure
5. T his is because a lower d‾ reduces both borrowers' consumption (the part d‾ in the
aggregate demand, as they can borrow less) and savers' consumption (via CS implicitly, as
their wealth is lower eventually), whereas a higher d0 only reduces the former. A policy
insight is that a restrictive leverage regulation is more devastating than the excessive
leverage it regulates.

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Enlarge
Implications for Fiscal Policies
A liquidity trap induced by leverage regulation has di erent policy implications, too. A
typical prescription from Keynesian IS-LM theory is that scal stimuli — such as
government spending and transfers — are powerful during the liquidity trap as they shift
the IS curve up without the crowding out e ect from raising the interest rate. Another
popular narrative for scal transfers is that they encourage consumption among cashconstrained consumers and boost aggregate demand toward the potential output.
In the regulation-induced liquidity trap, however, scal transfers will have limited e ects for
three reasons.
High Interest Rates

First, savers consume little in the liquidity trap not because they are cash constrained but
because — even if nominal interest rates are low — the real interest rate is so high that
they prefer saving to consumption. So, any scal transfers to the savers will mostly be
saved rather than consumed. Consumption-based transfers like consumption vouchers
might work, but agents can always substitute cash purchases with the vouchers without
raising their consumption much.
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Taxes

Second, if the scal transfers are nanced by raising public debt (which is ultimately paid
for by future taxes), agents will save the transfers for the future tax payment: the logic of
Ricardian equivalence. Essentially, debt- nanced transfers are like forced borrowings:
borrowing the transfers today and paying back the transfers plus taxes tomorrow. T hus,
the savers' supply curve in the debt market in Figure 2 shifts to the right (from saving the
transfers) but is completely absorbed by the increased government debt. T hus, the net
supply curve is the same.
Market Frictions

T hird, note that Ricardian equivalence holds if the debt market is complete and frictionless,
which is the case for savers but not the case for borrowers due to the debt limit. So, in
principle, transfers to borrowers would increase their consumption since they have a
higher marginal propensity to consume and always want to leverage to consume but
cannot. However, this channel only works because debt- nanced transfers are essentially
borrowing without being subject to the debt limit. If the tax obligations were counted
toward the debt limit, then the stimulus e ect of the borrowers would be gone.
In other words, transfers to borrowers could stimulate aggregate demand, but only
because it indirectly reduces the debt limit. T herefore, the root of the stimulus e ect is still
the restrictive leverage regulation.

Fiscal Transfer Multipliers
What will be the multiplier of the scal transfers during a regulation-induced liquidity trap?
In this case, borrowers will consume all the transfers, so we have CB=Y−d0+d‾+T , where T
is the amount of the debt- nance transfers to borrowers and savers. Ricardian equivalence
implies that the savers' consumption CS is the same. Summing these two, the aggregate
demand curve shifts up in Figure 5. If savers have a bigger share of the economy, the
aggregate demand curve will be atter, the shift up will be lower, and hence the multiplier
will be smaller (and it would equal 1 when savers and borrowers have equal shares).
In sum, scal transfers will have limited e ects on output during a regulation-induced
liquidity trap. Nevertheless, large enough transfers can lift the economy out of the liquidity
trap, despite not being very e ective. Of course, it would be easier to lift the economy by
relaxing the leverage regulations. But when rolling back the leverage regulations is not an
option (for example, in the Macbethian tragedy scenario), scal transfers could be the
next-best option.

What's Next?
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Back to China: Containing excessive leverage — as is the goal of any macroprudential
policy — is generally right for minimizing the risk of a liquidity trap. T his article highlights
the narrow corridor of regulating excessive leverage: Imposing too-restrictive leverage
regulation will only make the liquidity trap more likely.
Bearing this in mind, what should we pay attention to next? Based on the above analysis,
let's conclude with the following scenarios that would make a liquidity trap more likely.
Pessimism: Pessimistic households and investors more concerned about China's
downside risks will save more. T his would shift down both the aggregate demand
curve (lower CS) and the supply curve in the debt market (lower MRS).
De ation expectations: Expecting de ation would raise the lower bound for the real
interest rate in the debt market. A larger output gap is thus needed to maintain the
interest rate at the lower bound (lower CS), which adds to the de ation pressure and
ful lls the de ation expectation.
Collapse in real estate prices: If real estate properties are pledged as collateral, a
price collapse will trigger a forced deleverage.
Bank runs: On top of widening the output gap, bank runs would also reduce the
supply of savings to maintain the interest rate at the zero lower bound.
Russell Wong is a senior economist in the Research Department at the Federal Reserve
Bank of Richmond.

1 For a historical review of China's nancial policies, see the 2020 paper "Macroeconomic E ects

of China's Financial Policies" by Kaiji Chen and Tao Zha.
2 For example, see the 2012 paper "Debt, Deleveraging and the Liquidity Trap: A Fisher-Minsky-

Koo Approach" by Gauti Eggertsson and Paul Krugman, the 2016 paper "Liquidity Trap and
Excessive Leverage" by Anton Korinek and Alp Simsek and the 2016 paper "A Theory of
Macroprudential Policies in the Presence of Nominal Rigidities" by Emmanuel Farhi and Ivan
Werning.
3 To be precise, the saver's MRS is given by: MRSS(dS)=U′[Y+d-1S−dS/(1+r)]U′

[Y+dS−d+1S/(1+r+1)]/(1+ρ)−1, where U′(C) is the marginal utility of consumption, Y is income, ρ is
the rate of time preference and the subscripts of "+1" and "-1" denote the variables in the next and
previous periods, respectively. The saver's consumption is CS=Y+d-1−dS/(1+r) today and
C+1S=Y+dS−d+1S/(1+r+1) tomorrow.
4 Similarly, the borrower's MRS is given by: MRSB(dB)=U′[Y−d-1B+dB/(1+r)]U′

[Y−dB+d+1B/(1+r+1)]/(1+ρ)−1.
5 In the steady state, we have d+1S=d+1B=d=d0, Since d0S=d0B=d0, substituting this equality in

the de nition of MRS, we have r+1=r=ρ.
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6 Note that the saver's MRS under the leverage regulation becomes: MRSS(d‾)=U′[Y+d0−d‾/(1+r)]U′

[Y+ρd‾/(1+ρ)]/(1+ρ)−1 end entire equation.
7 In particular, CS solves U′(CS)=U′[Y+ρd‾/(1+ρ)]/(1+ρ).
8 To be precise, M=CS−Y+θ/(1+r)

To cite this Economic Brief, please use the following format: Wong, Russell. (April 2024) "Can

China Avoid a Liquidity-T rap Recession? Some Unintended Consequences of
Macroprudential Policies" Federal Reserve Bank of Richmond Economic Brief, No. 24-12.

T his article may be photocopied or reprinted in its entirety. Please credit the author,
source, and the Federal Reserve Bank of Richmond and include the italicized statement
below.
Views expressed in this article are those of the author and not necessarily those of the Federal
Reserve Bank of Richmond or the Federal Reserve System.

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