Heterogeneous-Agents | Macro Paper Warehouse

A Temporary VAT Cut as Unconventional Fiscal Policy

Mon, 01 Jan 0001 00:00:00 +0000

The paper studies Germany’s temporary 3 percentage-point VAT cut from July 1 to December 31, 2020 (standard rate 19%→16%, reduced rate 7%→5%), combining two causal identification strategies with microdata and a HANK model to establish that intertemporal substitution drove a large spending response concentrated in durable goods.

Ex-ante approach (July 2020 BOP-HH survey, fielded immediately after the cut took effect): The survey distinguishes households informed about the January 2021 reversal (treated) from those who believed the cut was permanent (control). Treated households are approximately 10 percentage points more likely to increase durable purchases on the extensive margin. This is a lower bound on the intertemporal substitution effect because some “control” households likely learned about the reversal before the survey, attenuating the control group’s spending behavior toward that of the treated group.

Ex-post approach (January 2021 BOP-HH survey and GfK scanner data): Cross-household variation in perceived VAT pass-through identifies the spending effect. Households perceiving high pass-through — who saw prices actually fall at their usual stores — spent approximately 37 percent more on durables in 2020HY2 than those perceiving low or no pass-through (preferred OLS/IV specification, Table 3). GfK scanner data on semi-durables shows approximately 10 percent higher spending for high vs. low perceived pass-through (coefficient ≈ 0.093, Table 5). Non-durable spending shows no statistically significant response. The magnitude of the response increases with the durability of the good and increases over time toward the December 2020 cutoff, consistent with intertemporal substitution (a more durable good generates larger discounted savings from buying before the reversal; a later purchase locks in savings for longer until January).

Direct evidence of intertemporal pull-forward (Table 4): Households reporting high perceived pass-through in 2020HY2 planned to spend approximately 1,642 EUR less on durables in 2021 first-half relative to those with low pass-through in the GfK survey — a direct “spend now, buy less later” pattern confirming temporal shifting rather than a pure income effect.

Cross-sectional heterogeneity: The response is driven by young, low net-wealth households and price-sensitive “bargain hunters” who actively compare prices across stores. Critically, the response is NOT concentrated in financially literate households or those reporting long planning horizons, which distinguishes the VAT policy from forward guidance (which requires understanding and acting on future rate paths) and implies the policy reaches a broad spectrum of household types.

No COVID-19 confound: The paper finds no significant interaction between a household’s pandemic exposure (work disruption, income loss, health shock) and its durable spending response, confirming the intertemporal substitution mechanism operated independently of the concurrent COVID-19 environment.

HANK model (based on the Bayer, Born, Luetticke 2024a two-asset heterogeneous-agent New Keynesian framework, adapted with illiquid durable goods and a Calvo durable-adjustment friction):

Durable adjustment probability per semi-annual period: λ = 18% (Calvo friction calibrated to the spread of the durable spending response through 2020HY2)
Perceived-pass-through heterogeneity: 65% of households perceive high pass-through; perceived average cut among treated = 2.4pp (both calibrated to BOP-HH data)
Calibration targets: durable spending response elasticity = 0.32; X/Y = 0.08 (durable expenditure share); B/Y = 0.86 (liquid bond share); (B+qΠ)/Y = 1.90 (total liquid wealth); G/Y = 0.29; top-10% wealth share = 52%; fraction liquidity-constrained = 18%
Structural parameters: β = 0.92 (semi-annual discount factor); ξ = 2.0 (CRRA coefficient); ϑ = 0.5 (Frisch labor supply elasticity); ν = 0.80 (non-durable expenditure weight); τc = 17.5% (baseline VAT rate); τ = 31% (income tax rate); δ = 5% (semi-annual durable depreciation rate)
Impact effects: total consumption +4.3%; durable consumption +29.4%; the VAT-inclusive price level falls by approximately 1.0pp on impact (less than the 2.4pp perceived cut because of demand-driven upward pressure on prices)
Multipliers at ELB: impact consumption multiplier = 3.0; cumulative two-year consumption multiplier = 1.7
Multipliers with Taylor rule: impact = 2.2; cumulative two-year = 0.9 (lower because the central bank raises nominal rates in response to the demand boost, partly crowding out consumption)
Decomposition: the direct effect — computed holding GE equilibrium objects (wages, asset prices, aggregate demand) fixed — accounts for approximately 90% of the durable consumption response and approximately 4/5 of the non-durable response; the remaining indirect effect operates through positive Keynesian income spillovers
Comparison to interest rate cuts: the VAT cut delivers a larger aggregate consumption response per unit of fiscal cost than a comparable nominal interest rate reduction, because interest rate cuts create countervailing income effects for net savers (who lose interest income) that partially offset the stimulus for net borrowers

Scope conditions: Empirical estimates are local to Germany’s 2020 economic environment (near-zero ECB policy rate, partial COVID-19 demand suppression). The causal identification exploits cross-household variation in perceived pass-through, instrumented by bargain-hunting behavior; the exogeneity assumption requires that price-searching behavior affects spending through perceived prices rather than through other channels. The HANK quantitative results are conditional on the Calvo durable adjustment friction and the 65%/35% perceived-pass-through split; sensitivity to these calibration choices is explored but not the primary focus.

Note on working paper versions: This summary is based on NBER Working Paper 29442 (August 2024 revision), which uses a HANK framework and reports a 4.3% impact on total consumption. A Bundesbank Discussion Paper (24/2025, April 2025) describes the model as a “RANK” (representative-agent) framework with a 4.4% impact. The published RES version (June 2026) may differ from both working paper versions in its model specification; the core empirical findings (37% durable response, 10% semi-durable response, 10pp ex-ante effect) are unlikely to have changed.

Summary of a forthcoming paper, AI-assisted and human-reviewed. See the linked original for the authoritative claims and full conditions.

In depth

Q1. What is the ex-ante identification strategy, and what does it identify?

The July 2020 BOP-HH survey ran immediately after the VAT cut took effect and identifies the causal effect of expecting a tax cut to be temporary by comparing households informed about the January 2021 reversal (treated) with those who believed the cut was permanent (control); treated households are approximately 10 percentage points more likely to report an intention to increase durable purchases. This is a lower bound on the true intertemporal substitution effect: if some “control” households learned about the reversal through other channels between the survey date and December 2020, they would have behaved more like treated households, compressing the gap. The ex-ante design also measures the extensive-margin decision (whether to increase purchases) rather than the total spending level, so the 10pp estimate is not directly comparable to the 37% ex-post level estimate.

Q2. What is the ex-post identification strategy, and how does it address endogeneity?

The January 2021 BOP-HH survey asks respondents how their 2020HY2 spending compared to a counterfactual without the VAT cut, and instruments perceived price pass-through with bargain-hunting behavior (price comparison across stores) — a variable that predicts who notices price changes but should not directly affect intertemporal allocation decisions. OLS and IV estimates are close (Table 3), suggesting limited endogeneity bias; the IV result of 37% more durable spending for high vs. low perceived pass-through is the preferred causal estimate. GfK scanner data provides an independent corroboration using objective purchase records rather than survey recall, yielding the 10% semi-durable estimate (Table 5, coefficient ≈ 0.093 in IHS-transformed spending).

Q3. Why does the response increase with the durability of the good?

A durable good yields a flow of consumption services over multiple periods; purchasing it before the January 2021 VAT reversal locks in tax savings for the entire lifetime of the good, while purchasing a non-durable before the reversal saves taxes only on a single-period consumption unit — so the present-discounted-value gain from intertemporal substitution is proportional to the good’s durability. This prediction is confirmed empirically: durables (white goods, electronics) show the largest response (37%); semi-durables (clothing, textiles in GfK) an intermediate response (~10%); non-durables no significant response. The fact that the spending response also builds toward the December cutoff — with the largest response in November and December 2020 — further supports intertemporal substitution (households delay purchases even within the cut period, maximizing the remaining time advantage).

Q4. Why was the VAT cut effective despite the concurrent COVID-19 shock?

The paper finds no statistically significant interaction between household-level COVID-19 exposure (income loss, work disruption, health shock) and the durable spending response to the VAT cut; the intertemporal price channel operated independently of pandemic-related income and uncertainty effects. This is consistent with the bargain-hunting interpretation: price-sensitive households who actively compare prices adjusted toward durables regardless of their pandemic-specific economic circumstances. The finding also implies that the simultaneous COVID-19 shock does not confound the identification, because the cross-household variation in perceived pass-through is independent of COVID-19 exposure.

Q5. Why is a HANK model appropriate, and what does durable heterogeneity add?

A HANK model is needed because the spending response is driven disproportionately by young, low net-wealth households who face binding liquidity constraints at some frequencies — in a representative-agent model all households respond immediately to the intertemporal price signal, which would predict an immediate front-loaded response; in the HANK model with Calvo durable adjustment, constrained households adjust their durable stock only when they receive an adjustment opportunity (λ=18% per semi-annual period), spreading the response through time and matching the observed gradual build-up of durable spending through 2020HY2. The illiquid-durable extension of the Bayer-Born-Luetticke framework separately tracks liquid financial assets and illiquid durables, allowing the model to capture both the temporal dynamics of the spending response and the cross-household variation in responses across the wealth distribution.

Q6. What is the impact consumption multiplier, and why is it larger at the ELB?

The impact consumption multiplier — the increase in total consumption divided by the fiscal cost of the VAT cut (measured as the VAT rate reduction times baseline consumption) — is 3.0 at the effective lower bound (ELB) and 2.2 with an active Taylor rule. At the ELB, the demand boost from the VAT cut raises inflation expectations; since the nominal rate cannot rise, the real rate falls, providing a secondary stimulus through the inter-temporal Euler equation; with an active Taylor rule, the central bank raises the nominal rate in response to higher inflation, crowding out some consumption and reducing the multiplier. The 3.0 impact multiplier exceeds the standard Keynesian multiplier because the durable sector amplifies the effect: a 2.4pp perceived price cut induces a 29.4% jump in durable purchases, whose production generates large income spillovers.

Q7. Why does the cumulative two-year multiplier fall below the impact multiplier?

The cumulative two-year multiplier is 1.7 at the ELB (vs. 3.0 on impact) because durable purchases pulled forward into 2020HY2 create a “payback effect” — households that already upgraded their durables need fewer new purchases in 2021, reducing durable consumption below the counterfactual path for several quarters after the reversal. This is directly documented in Table 4: high perceived pass-through households planned to spend approximately 1,642 EUR less on durables in 2021H1, and the GfK data confirms a spending decline in early 2021. The cumulative multiplier remains above zero and above 1.0, confirming the policy provides net stimulus over the two-year horizon even accounting for the post-cut hangover.

Q8. Why is the VAT cut more powerful than a comparable interest rate cut?

An interest rate cut stimulates borrowers but simultaneously reduces interest income for net savers, who partially offset their reduced income by consuming less; the VAT cut lowers current prices for all households without changing the interest rate, so there is no countervailing income effect for savers, and the consumption stimulus is less diluted by redistribution. In the HANK calibration, the additional dimension is that the VAT cut operates through a perceived price channel that requires only that households notice lower prices in stores — a much lower bar than the financial sophistication required to respond to forward guidance or interest rate signals — so the policy reaches a broader share of the household distribution than monetary easing.

Q9. What does the distributional evidence imply for fiscal stimulus design?

Young, low net-wealth households respond most strongly to the VAT cut, the opposite of the pattern expected if the response required financial sophistication; combined with the bargain-hunting identification, this implies the policy’s effectiveness does not depend on forward-looking planning or consumption-smoothing capacity — it is triggered simply by noticing prices are lower at the store. This finding challenges the conventional view that temporary fiscal policies are less effective than permanent ones because households do not optimize over them; instead, the price-noticing channel bypasses the forward-looking optimization entirely and generates a large spending response among households who do not match the life-cycle model assumptions. The distributional progressivity (young, low-wealth households drive the response) also contrasts with unconventional monetary policy (which benefits asset-holders through wealth effects) and improves the equity case for temporary VAT cuts as a stimulus instrument.

Key concepts

intertemporal substitution : the mechanism by which a temporary price reduction — here a VAT cut that will be reversed — induces households to shift consumption from the post-cut period to the cut period; the paper’s primary transmission channel, more powerful for durable goods because the present-value savings scale with the good’s lifetime.

perceived pass-through : the fraction of the statutory VAT rate reduction that a household perceives as an actual reduction in the prices it faces in its usual stores; the paper’s main source of cross-sectional identification in the ex-post strategy, correlated with bargain-hunting behavior.

ex-ante approach : the identification strategy using the July 2020 BOP-HH survey; identifies the causal effect of expecting a cut to be temporary by comparing informed (reversal known) vs. uninformed (thought permanent) households on their intended durable purchase behavior.

ex-post approach : the identification strategy using the January 2021 BOP-HH survey and GfK scanner data; identifies the causal effect of perceived price changes on realized spending by comparing high vs. low perceived pass-through households and instrumenting with bargain-hunting behavior.

payback effect : the reduction in durable spending in 2021H1 among households that pulled forward purchases during the 2020 cut; documented through the 1,642 EUR planned spending gap in Table 4 and GfK scanner data; makes the cumulative two-year multiplier (1.7) substantially lower than the impact multiplier (3.0).

HANK model with durable Calvo friction : the Bayer-Born-Luetticke (2024a) two-asset heterogeneous-agent New Keynesian framework adapted with illiquid durable goods and a Calvo probability of durable adjustment (λ = 18% per semi-annual period); the Calvo friction matches the gradual build-up of the durable spending response through 2020HY2 rather than an immediate front-loaded spike.

Monetary and Macroprudential Policy and Welfare in an Estimated Four‐Agent New Keynesian Model

Mon, 01 Jan 0001 00:00:00 +0000

This paper introduces a four-agent estimated New Keynesian DSGE model—comprising banked simple households, underbanked simple households, firm owners, and bank owners—to examine agent-specific and social welfare effects of monetary and macroprudential policy, estimated on U.S. quarterly data (1985Q1–2016Q4) via Bayesian methods. The model features two layers of endogenous default probability (for borrowers and banks), nominal, real, and financial frictions, and trend inflation and stochastic growth. The optimal bank capital requirement ratio (CRR) is estimated at 12.6%, which is 2.1% above Basel III’s 10.5%; increasing CRR up to approximately 12.2% raises welfare for all four agent types, though with smaller gains for credit-reliant simple households and firm owners. Countercyclical capital buffers benefit firm owners and bank owners with smaller gains for simple households. Coordinated monetary and macroprudential policy yields higher social welfare than non-coordinated policies.

Summary of a forthcoming paper, AI-assisted and human-reviewed. See the linked original for the authoritative claims and full conditions.

In depth

Q1. Why does the paper use four agent types instead of the usual borrower-saver distinction?

The standard borrower-saver split lumps together all interest-earning agents—including both simple deposit-holding households and wealthy bank owners—so that macroprudential policies that shift surplus from borrowers to savers appear to benefit the simple household and the banker equally; the four-agent framework separates these groups and allows for heterogeneous welfare effects. Population shares are calibrated using Compustat and the Survey of Consumer Finances (firm owners and bank owners as shareholders of non-financial and financial firms) and the National Survey of Unbanked and Underbanked Households (underbanked simple households with very limited access to banking services).

Q2. What is the optimal CRR and how does it compare to existing benchmarks?

The optimal social CRR is estimated at 12.6%, which is 2.1% higher than Basel III’s 10.5%, 4.6% higher than Basel II’s 8%, and 3.6% higher than the 9% optimal CRR of Mendicino et al. (2019) who use a borrower-saver welfare framework. Increasing the CRR up to approximately 12.2% improves welfare for all four agent types, though unequally: simple households and firm owners who rely on credit see smaller gains. Above 12.2%, stricter CRR harms firm owners and simple households (tighter credit reduces activity), while bank owners continue to gain via higher capital income share until the CRR exceeds 25.9%, above which even bank owners are harmed as loans fall dramatically.

Q3. How do countercyclical capital buffers and loan loss provisions affect welfare by agent type?

Countercyclical capital buffers support firm owners and bank owners with smaller gains for the two simple household types; countercyclical loan loss provisions improve social welfare only for specific shocks and benefit underbanked simple households and firm owners at the expense of bank owners and banked simple households. The asymmetry reflects the different income streams: bank owners’ income derives primarily from loan returns and capital gains on bank equity, while underbanked simple households are most sensitive to credit availability. Loan loss provisions affect the timing of income recognition and loss absorption, generating distributional trade-offs that differ from those of capital requirements.

Q4. What are the gains from coordinating monetary and macroprudential policy?

Coordinating monetary and macroprudential policy yields higher social welfare than assigning each policy to an independent authority targeting its own objective, demonstrating that the interaction between interest rate policy and bank capital regulation matters for welfare outcomes. Investment shocks (27.41% of GDP growth variance) and financial risk shocks (~20%) are quantitatively important in this interaction. The model’s rich friction structure means that optimal monetary policy must account for how macroprudential policy changes the credit supply environment, and vice versa; failing to coordinate creates inefficiencies that coordinated policy avoids.

Key concepts

four-agent model : the model’s typology distinguishing banked simple households, underbanked simple households, firm owners, and bank owners; enables agent-specific welfare analysis of macroprudential policy with heterogeneous income streams and credit access. optimal capital requirement ratio (CRR) : the bank capital-to-assets ratio that maximizes social welfare; estimated at 12.6% in this model; 2.1% above Basel III’s current 10.5% requirement. countercyclical capital buffer (CCyB) : a macroprudential tool requiring banks to hold additional capital during economic expansions to be released in downturns; shown here to benefit firm owners and bank owners with smaller gains for simple households. dynamic loan loss provisions : a macroprudential tool requiring banks to build provisions against future expected losses during expansions; shown here to have welfare effects that depend on the source of the shock and to benefit different agent types than capital requirements.

Present Bias Amplifies the Household Balance-Sheet Channels of Macroeconomic Policy

Mon, 01 Jan 0001 00:00:00 +0000

Layer 1 — Summary

Maxted, Laibson, and Moll study fiscal and monetary policy in a partial-equilibrium heterogeneous-agent model in which homeowners have present-biased time preferences (Instantaneous Gratification preferences, the continuous-time limit of quasi-hyperbolic discounting) and naive beliefs, alongside a liquid savings account, an illiquid home, and access to credit card and mortgage debt. Because present bias substantially increases households’ marginal propensity to consume — in the calibrated model the quarterly MPC rises from 4% under exponential discounting to 14% under present bias, and the quarterly marginal propensity for expenditure (MPX) rises from 13% to 30% — present bias powerfully increases the effect of fiscal stimulus. Present bias also amplifies the overall effect of expansionary monetary policy, but at the same time slows down the speed of monetary transmission: interest rate cuts incentivize households to conduct cash-out refinances, which become targeted liquidity injections to households near the liquidity constraint who have especially high MPCs, but present bias with naive beliefs also introduces a motive for households to procrastinate on refinancing their mortgage, which substantially slows the speed at which this channel operates. A noteworthy feature of the model is that present bias amplifies the direct effect of monetary policy on household consumption while simultaneously delivering larger MPCs — a combination that is in contrast to standard heterogeneous-agent models, where modeling choices that amplify MPCs typically deliver smaller consumption responses to interest rate changes. The calibrated present-biased economy also replicates several empirical regularities that are difficult to match with exponential discounting: high-cost credit card borrowing by homeowners, empirically plausible cash-out behavior and loan-to-value ratios, and refinancing inertia.

In depth

Q1. Q: What is the core modeling innovation and why is it needed?

A: The paper introduces naive Instantaneous Gratification (IG) preferences — the continuous-time limit of quasi-hyperbolic (beta-delta) discounting — into a two-asset heterogeneous-agent model with a liquid savings account and illiquid home equity accessible via mortgage refinancing. The naivete assumption (households do not foresee their own future present bias) is essential because it generates procrastination: naive households perpetually intend to refinance “soon” but keep delaying. A model with exponential discounting that merely sets parameters to match empirical MPCs would not generate procrastination behavior, and would require implausible interest rate calibrations (very low credit card rates or very high illiquid asset returns) to simultaneously match low liquid wealth accumulation and high credit card borrowing. Present bias with interest rates taken from the data resolves both issues.

Q2. Q: What are the key quantitative MPC results and why do they matter for fiscal policy?

A: In the exponential discounting benchmark, the quarterly MPC is 4% and the quarterly MPX (which includes nondurables and durables) is 13%. Under the present-bias benchmark, the MPC rises to 14% and the MPX rises to 30%. The empirical literature estimates quarterly nondurable spending responses on the order of 15%–25%, and total expenditure responses typically two to three times larger, so the present-biased model is substantially more consistent with the data. Because fiscal stimulus (modeled as an unexpected one-time lump-sum payment, financed by a flow income tax) operates through household spending propensities, the higher MPCs and MPXs under present bias directly and powerfully increase the aggregate consumption response to fiscal policy relative to the exponential benchmark.

Q3. Q: How does present bias amplify the effect of monetary policy?

A: Interest rate cuts incentivize households to conduct cash-out refinances — they borrow against accumulated home equity, converting illiquid home equity into liquid wealth. Because this liquidity is targeted to households who are near their borrowing constraint (and thus have especially high MPCs), the aggregate consumption response to a given rate cut is amplified. Crucially, present bias amplifies this channel beyond the exponential benchmark precisely because higher MPCs mean each dollar of liquidity injected generates more consumption. This stands in contrast to the standard result in the heterogeneous-agent literature (Auclert 2019; Olivi 2017; Kaplan, Moll, and Violante 2018) that MPC-amplifying modeling choices reduce the consumption response to interest rate changes because MPC enters the substitution effect with a negative sign in standard one-asset models. The two-asset structure with home equity and the cash-out refinance channel breaks this trade-off.

Q4. Q: How does present bias slow the speed of monetary transmission?

A: Present bias with naive beliefs introduces a motive for households to procrastinate on refinancing their mortgage. Refinancing is an immediate-cost, delayed-reward task: it requires the borrower to spend weeks gathering documents, filling out paperwork, and negotiating with lenders, with benefits (lower mortgage payments or extracted home equity) accruing afterward. Naive present-biased households discount current effort costs very heavily relative to future benefits, so they delay, all the while (counterfactually) believing they will complete the task in the near future. This procrastination substantially slows down the speed at which the cash-out refinance channel of monetary policy operates: even though a rate cut eventually incentivizes households to refinance and extract equity, the timing of that response is stretched out relative to what exponential discounters would do.

Q5. Q: What is the role of naive beliefs versus sophisticated (partially or fully aware) present bias?

A: Naivete is necessary to generate procrastination from small effort costs. A fully sophisticated present-biased household (one who correctly anticipates its own future self-control problems) would not indefinitely defer a task it correctly anticipates will keep being deferred. The paper extends the analysis to partial and full sophistication in Online Appendix D.5. The key takeaway is that procrastination — and thus the speed-reduction effect on monetary transmission — is driven by at least partial naivete. The MPC-amplification and fiscal-policy amplification results are more robust across sophistication levels.

Q6. Q: What empirical regularities does the present-biased calibration match that the exponential model cannot easily match?

A: The present-biased economy replicates: (1) empirically plausible levels of high-cost credit card debt held simultaneously with home equity (a puzzle under exponential discounting); (2) cash-out behavior and loan-to-value ratios consistent with data; (3) a buildup of liquidity-constrained households consistent with empirical propensities to spend out of credit card limit increases (Gross and Souleles 2002; Agarwal et al. 2018); (4) consumption function discontinuities at the borrowing constraint consistent with Ganong and Noel (2019); (5) MPCs and MPXs that remain elevated for large shocks (Fagereng, Holm, and Natvik 2021); (6) the intertemporal MPC profile consistent with Auclert, Rognlie, and Straub (2018); (7) differential MPCs out of liquid versus illiquid transfers (Ganong and Noel 2020); and (8) refinancing inertia — the proclivity for households to delay refinancing when financially optimal (Keys, Pope, and Pope 2016; Johnson, Meier, and Toubia 2019; Andersen et al. 2020).

Q7. Q: What is the model’s scope — what does it abstract from?

A: The model is set in partial equilibrium, so general equilibrium effects (e.g., endogenous interest rate responses, aggregate demand externalities) are not captured; the authors describe their results as inputs for a fuller general equilibrium analysis. The model focuses on homeowners (two-thirds of U.S. housing units), abstracting from renters. House prices are fixed (consistent with their slow movement over short horizons), with an extension to house price shocks in Online Appendix D.2.1. The model does not allow for home equity lines of credit, second mortgages, or reverse mortgages, because these products are more commonly used when interest rates are rising, and the paper focuses on the stimulative effect of rate cuts. The interest rate in the model is a long rate (e.g., 10-year TIPS), with the implicit assumption that the Federal Reserve implements the necessary short-rate adjustments.

Q8. Q: How does the present-biased model compare to the standard HANK picture on the monetary-MPC trade-off?

A: In standard one-asset heterogeneous-agent models, a household’s MPC is a sufficient statistic that enters the substitution effect of interest rate changes with a negative sign — so modeling choices that raise MPCs reduce monetary policy effectiveness. The present-biased two-asset model breaks this result: because interest rate cuts trigger cash-out refinances that inject liquidity targeted to high-MPC households near the constraint, higher MPCs translate into larger, not smaller, aggregate consumption responses to monetary policy. Present bias therefore simultaneously amplifies fiscal policy (via higher MPCs) and amplifies the overall effect of monetary policy (via the targeted liquidity channel), while introducing the procrastination-driven speed reduction as the offsetting cost.

Key Concepts

Present bias (Instantaneous Gratification preferences): The paper uses “present bias” to refer to quasi-hyperbolic discounting. In the continuous-time limit (Instantaneous Gratification, or IG, preferences, following Harris and Laibson 2013), the current self discounts all future selves by factor β < 1, while exponential discounting of the future (rate ρ) applies from any future vantage point. This creates a discontinuity in the discount function at t = 0 whenever β < 1. Setting β = 1 recovers standard exponential discounting.

Naive beliefs: Households do not foresee their own future present bias. The current self believes all future selves will be exponential discounters (β = 1), even though this belief is incorrect. Naivete is what transforms present bias into procrastination: the household perpetually expects its future self to complete effortful tasks, but each future self faces the same bias.

Cash-out refinance channel: When market interest rates fall, households have an incentive to refinance their fixed-rate mortgage, locking in a lower interest rate. If the household has accumulated home equity (illiquid), it can simultaneously borrow against that equity — a cash-out refinance — converting illiquid home equity into liquid wealth. In the model, this acts as a targeted liquidity injection to households near their borrowing constraint (who have high MPCs), amplifying the aggregate consumption response to rate cuts.

Procrastination motive: Present bias introduces a motive to procrastinate on immediate-cost, delayed-reward tasks such as mortgage refinancing. The effort and paperwork costs of refinancing are borne immediately, while the financial benefits accrue over time. A naive present-biased household heavily discounts the current effort cost relative to future benefits, leading it to defer refinancing repeatedly. This substantially slows the speed at which the cash-out refinance channel of monetary policy operates.

Marginal propensity to consume (MPC) vs. marginal propensity for expenditure (MPX): The paper distinguishes the quarterly MPC (response of nondurable consumption to a one-unit cash transfer) from the quarterly MPX (which also includes durables). Under exponential discounting, MPC = 4% and MPX = 13%; under the present-bias benchmark, MPC = 14% and MPX = 30%. The higher MPXs are more consistent with empirical estimates (quarterly nondurable responses of 15%–25%; total spending responses two to three times larger).

Refinancing inertia: The empirical regularity that households delay mortgage refinancing even when it is financially optimal to do so. The paper provides a theoretical foundation for this behavior through the procrastination motive generated by naive present bias combined with the small effort cost of refinancing.

Summary based on LSE Research Online published version. AI-assisted, human review pending.

Redistributive Policy Shocks and Monetary Policy with Heterogeneous Agents

Mon, 01 Jan 0001 00:00:00 +0000

Layer 1 — What this paper finds and why it matters

Governments in emerging market and developing economies (EMDEs) routinely intervene in agricultural markets — procuring grain and redistributing it to poor households — in response to food price shocks or expanded food security mandates (India’s 2013 National Food Security Act is the leading example). This paper asks how monetary policy should respond to such “redistributive policy shocks,” and what those shocks do to sectoral inflation and the consumption distribution between rich and poor households. The authors build a two-sector (agriculture with flexible prices; manufacturing with sticky prices), two-agent (Ricardian rich; rule-of-thumb poor) New Keynesian DSGE model, calibrated to India, that extends the TANK framework of Debortoli and Gali (2018) to two sectors and introduces explicit government procurement and redistribution. They show that a redistributive policy shock raises aggregate inflation and the output gap but also raises poor consumption and aggregate welfare, because the subsidy-in-kind effect on poor households more than offsets the decline in rich consumption and the inflationary pressure. They further show that consumer heterogeneity matters for whether monetary policy responses to various shocks raise or reduce aggregate welfare: in models with a flexible-price agricultural sector, contractionary monetary shocks produce larger deflation but smaller declines in real consumption relative to one-sector benchmarks, so the welfare cost of monetary contraction is lower than standard NK models imply.

Summary based on MPRA working paper (No. 101651, July 2020). The extracted PDF text was truncated before the calibration, impulse response, and welfare sections; quantitative parameter values and figure-level results are not available in the source text used here. AI-assisted, human review pending. See the linked original for authoritative claims.

In depth

Q1. What is a “redistributive policy shock” and how does the model capture it?

A redistributive policy shock is a sudden increase in the fraction of government-procured agricultural output that is redistributed to poor households. In the model, the government taxes rich (Ricardian) households via lump-sum levies each period, uses those proceeds to purchase agricultural output at the open market price, and then redistributes a fraction φ_t of the procured quantity to poor households as an in-kind subsidy. The remaining fraction goes into a buffer stock. The shock to redistribution is modeled as a positive innovation to φ_t (AR(1) process), distinct from a shock to the procurement quantity Y^P_{A,t} itself. Because the in-kind transfer reduces the effective price paid by the poor for agricultural goods — the poor face an effective price of (1 − λ_t)P_{A,t} — the redistributive shock operates as a proportional price subsidy on agriculture consumption for the poor, even though the quantity is what the government directly controls.

Q2. What are the two types of households and how do they differ?

Rich households are Ricardian (forward-looking) and hold one-period risk-free bonds; poor households are rule-of-thumb consumers who do not save. Both types consume goods from both the agricultural and manufacturing sectors according to Cobb-Douglas indices, but they differ in three ways. First, poor households have a higher budget share for agricultural goods (δ_P > δ_R), consistent with Engel’s Law. Second, the inverse of the intertemporal elasticity of substitution (IES) is higher for the poor (σ_P > σ_R), following Atkeson and Ogaki (1996) estimates for Indian household data; this means the poor are less willing to substitute consumption across time and respond differently to real wage changes. Third, rich households have both labor income and dividend income from monopolistically competitive manufacturing firms, while poor households have only labor income.

Q3. What happens to inflation and consumption when a positive agricultural productivity shock hits?

A positive agricultural productivity shock leads to a decline in inflation, a rise in the output gap, and higher consumption for both rich and poor households. Because the agriculture sector has flexible prices, a positive productivity improvement lowers agricultural prices immediately, reducing the terms of trade (the relative price of agriculture to manufacturing). Aggregate CPI inflation falls. The rise in agricultural output increases real income for both household types, raising consumption and aggregate welfare. These dynamics are compared to the Aoki (2001) representative-agent two-sector benchmark.

Q4. What are the aggregate and distributional effects of a positive redistributive policy shock?

A procurement-and-redistribution shock raises aggregate inflation, the output gap, and poor consumption, while lowering rich consumption; aggregate welfare rises because the redistribution effect dominates. The mechanism has two parts. First, the government procures additional agricultural output at the market price, financed by higher lump-sum taxes on the rich; this reduces rich consumption. Second, the redistributed grain lowers the effective price of the agricultural good for the poor, raising poor consumption through a “redistribution effect.” Because poor households spend a higher share of income on the agricultural good than rich households, and because the poor receive a fraction of their agricultural consumption for free, market demand for the agricultural good in the open market is less than it would be without redistribution. Consequently, the inflationary impact of the procurement shock is substantially lower in the two-agent model than in the Aoki representative-agent model (where there is no redistribution to dampen open-market demand).

Q5. How does consumer heterogeneity alter the transmission of a contractionary monetary policy shock?

In models with a flexible-price agricultural sector, a contractionary monetary shock produces a larger deflation but a smaller decline in consumption and smaller welfare losses than in single-sector or representative-agent benchmarks. A rise in the nominal interest rate induces intertemporal substitution of consumption, reducing aggregate demand and the aggregate price level. This deflationary effect is amplified when a flexible-price sector is present alongside the sticky-price sector, because agricultural prices can fall immediately. However, the same flexible-price sector means that real interest rates rise by less (compared to an all-sticky-price economy), so the reduction in rich and poor consumption is also smaller. The paper compares this to three benchmarks: the simple one-sector one-agent NK model (Gali 2015, Chapter 3), the Debortoli-Gali (2018) one-sector two-agent model, and the Aoki (2001) two-sector one-agent model. The welfare losses from monetary contraction are lower in the two-sector models (the authors’ framework and Aoki’s) than in the one-sector models.

Q6. How does the model differ from its three main benchmark frameworks?

The model merges the two-sector production structure of Aoki (2001) with the TANK distributional structure of Debortoli and Gali (2018), and adds explicit government procurement and redistribution — none of the benchmarks have all three features. Relative to Aoki: the paper adds poor/rich heterogeneity, different IES parameters, and the government redistribution mechanism. Relative to Debortoli-Gali: the paper adds an agricultural flexible-price sector and the redistribution shock, and assumes complete markets (Debortoli-Gali assumes incomplete markets; their model is treated as an approximation). Relative to Gali (2015, Chapter 3): the paper adds both a second sector and household heterogeneity. The three differences from the simple NK benchmark in the Dynamic IS and NKPC equations are: (i) the presence of a terms of trade channel, (ii) heterogeneous agents with different IES parameters and budget shares, and (iii) redistribution policy that shifts the effective price index of the poor.

Q7. What role do terms of trade play in the model’s transmission mechanism?

The terms of trade between agriculture and manufacturing (T_t = P_{A,t}/P_{M,t}) is a central transmission variable that affects both aggregate consumption and inflation. Aggregate CPI inflation can be decomposed as π_t = δ_R·π_{A,t} + (1 − δ_R)·π_{M,t} = δ_R·ΔT_t + π_{M,t}, so movements in the terms of trade feed directly into headline inflation. Total agricultural and manufacturing consumption both depend on T_t, rich consumption C_{R,t}, and poor consumption C_{P,t} through equations (22) and (23). A rise in the terms of trade (higher relative agricultural prices) makes the consumption basket of the poor more expensive because they spend a larger share of income on agricultural goods, inducing them to reduce agricultural purchases. This terms-of-trade channel is absent from one-sector benchmarks and is a key reason the paper’s framework generates different aggregate dynamics than Debortoli-Gali.

Q8. What is the welfare metric used, and what is the paper’s welfare conclusion?

Welfare is defined to depend on aggregate consumption in the standard fashion, and the paper’s central welfare conclusion is that consumer heterogeneity matters for whether monetary policy responses to shocks raise or reduce aggregate welfare. For a redistributive policy shock, aggregate welfare rises despite higher inflation, because the gain in poor consumption (driven by the subsidy) exceeds the loss in rich consumption and the distortionary cost of inflation. For a contractionary monetary shock, welfare losses are smaller in the two-sector framework than in single-sector frameworks, because the flexible-price agricultural sector moderates the real interest rate increase and limits the consumption decline. The paper does not report specific numerical welfare loss figures in the portion of text available in this source extract.

Key concepts

Redistributive policy shock : in this paper’s usage, a positive shock to the fraction (φ_t) of government-procured agricultural output that is redistributed to poor households as an in-kind subsidy; distinct from a procurement level shock. Modeled as an AR(1) process on φ_t.

TANK (Two-Agent New Keynesian) model : a tractable heterogeneous-agent NK framework with exactly two household types — Ricardian (forward-looking, hold bonds) and rule-of-thumb (hand-to-mouth, do not save) — that Debortoli and Gali (2018) showed provides a good approximation to the aggregate dynamics of a full HANK model.

Rule-of-thumb (hand-to-mouth) consumers : households that maximize static utility subject to a static budget constraint, consuming all current income each period. In this model, the poor are rule-of-thumb consumers with only labor income and no bond holdings.

Effective price of agriculture for the poor : P’{A,t} = (1 − λ_t)P{A,t}, where λ_t is the fraction of poor agricultural consumption provided for free via the redistributive subsidy. The poor face a price index P’t = {(1−λ_t)P{A,t}}^{δ_P} · P_{M,t}^{1−δ_P}, which differs from the rich price index.

Terms of trade (TOT) : T_t = P_{A,t}/P_{M,t}, the relative price of the agricultural good to the manufactured good. Changes in TOT affect the sectoral composition of consumption for both household types and transmit through the Dynamic IS and NKPC equations.

Intertemporal elasticity of substitution (IES) : 1/σ_K for household type K. The paper assumes σ_P > σ_R (poor have lower IES than rich), following Atkeson and Ogaki (1996) estimates for Indian household data; this differential drives asymmetric labor supply responses to real wage changes.

Procurement shock : a shock to the quantity Y^P_{A,t} of agricultural output the government procures each period, modeled as a separate AR(1) process from the redistribution-fraction shock. Together, the procurement level and redistribution fraction determine the total subsidy received by poor households.

Stock market participation and macro-financial trends

Mon, 01 Jan 0001 00:00:00 +0000

This paper documents a puzzle for canonical limited-participation models: when U.S. stock market participation rose from 31.6% to 53% between 1989 and 2007—a period also characterized by the Great Moderation—the equity premium and stock return volatility increased rather than fell as those models would predict. The paper resolves this puzzle using an RBC model with concentrated capital ownership in which capitalists have external habit utility with a habit stock that depends on aggregate per capita consumption. As participation rises, the representative capitalist’s consumption converges to aggregate consumption, shrinking the surplus-consumption ratio and raising endogenous average risk-aversion; this risk-aversion channel dominates the conventional risk-sharing channel (which predicts a lower equity premium under higher participation). The model implies that higher participation generates a sizeable rise in both the equity premium and stock return volatility while reducing the risk-free rate and aggregate consumption volatility—jointly explaining the observed U.S. macro-financial patterns. Household-level data from the Consumption Expenditure Survey (1984–2017) and cross-state variation support the model’s mechanism.

Summary based on a working paper version, AI-assisted and human-reviewed. See the linked published article for the authoritative version.

In depth

Q1. What is the puzzle the paper addresses?

Existing limited-participation models predict that higher stock market participation should reduce the equity premium (by improving risk-sharing), yet the U.S. experienced a rising equity premium and higher stock return volatility precisely during the period of sharp participation growth (1989–2007), at the same time as the Great Moderation. The standard channel predicts that as more households access financial markets, the representative capitalist’s risk burden falls and the covariance between capitalists’ consumption and equity returns declines, lowering the equity premium. The data contradict this prediction, motivating the paper’s novel mechanism.

Q2. What is the novel risk-aversion channel?

As stock market participation rises, the representative capitalist’s consumption converges toward aggregate per capita consumption, shrinking the surplus-consumption ratio and thereby raising the endogenous effective risk-aversion of the economy—this risk-aversion channel dominates the conventional risk-sharing channel. The key assumption is that capitalists’ habit stock depends on aggregate per capita consumption. The surplus-consumption ratio (the gap between the capitalist’s consumption and the habit level) determines risk-aversion in the external habit utility framework. As participation rises, the capitalist’s consumption approaches the habit level, increasing risk-aversion and the equity premium, even as aggregate consumption volatility falls.

Q3. What are the model’s predictions for macro-financial variables?

In the model economy, an increase in stock market participation generates a sizeable rise in both the equity premium and the volatility of stock returns, a moderate increase in the price-dividend ratio, and a fall in the average risk-free rate and aggregate consumption volatility—jointly accounting for the U.S. macro-financial experience since the 1980s. The rise in equity premium and stock volatility produced by higher participation substantially counteracts the shrinking effect due to lower aggregate uncertainty from the Great Moderation, providing a unified explanation for the co-movement of these macro-financial trends.

Q4. What is the empirical evidence supporting the mechanism?

Household-level data from the U.S. Consumption Expenditure Survey (1984–2017) show that the model-implied average risk-aversion for the representative stockholder trended upward over time closely tracking the rate of participation, while the stockholder-to-aggregate consumption ratio trended downward; cross-state data document a negative relationship between participation and the stockholder-to-aggregate consumption ratio. Both the time-series and cross-sectional patterns are consistent with the model’s prediction that higher participation compresses the gap between stockholder and aggregate consumption, the key driver of the risk-aversion channel.

Key concepts

participation puzzle : the empirical regularity that only a fraction of the population participates in the stock market; exploited in asset pricing models to explain the equity premium with plausible average risk-aversion; this paper studies the consequences of the upward trend in participation since the 1980s. surplus-consumption ratio : the gap between the capitalist’s consumption and their habit level, normalized by consumption; the key state variable in external habit utility models; determines endogenous risk-aversion so that a shrinking surplus-consumption ratio raises risk-aversion. risk-aversion channel : the novel mechanism introduced in this paper: as stock market participation rises, the capitalist’s consumption converges to aggregate consumption, shrinking the surplus-consumption ratio and raising endogenous risk-aversion and thus the equity premium; dominates the conventional risk-sharing channel in the model. risk-sharing channel : the conventional channel in limited-participation models: higher participation improves risk-sharing, reducing the covariance between stockholder consumption and equity returns and tending to depress the equity premium; present in the model but dominated by the risk-aversion channel.