Optimal Monetary Policy and Heterogeneous Agents in New Keynesian Economies

Macroeconomists and central bank advisors have long relied on the representative-agent New Keynesian framework to guide monetary policy decisions, treating households as if they share an identical economic experience. However, a newly released working paper published in October 2026 under Working Paper number 35967 and DOI 10.3386/w35967 challenges this traditional paradigm by exploring optimal monetary policy within a general heterogeneous-agent New Keynesian, or HANK, economy. Authored by leading economic theorists, the research paper moves away from conventional social welfare functions and instead constructs a framework where the policymaker maximizes the joint surplus of all households. By evaluating the resources left over if economic winners were to compensate losers, the study provides a profound reassessment of how central banks should manage interest rates and inflation in the face of widespread income and wealth inequality.

Using sophisticated linear-quadratic methods, the authors derive an approximate optimal policy that incorporates both traditional stabilization goals and the structural frictions inherent in modern, unequal economies. The resulting quadratic objective function successfully nests the standard New Keynesian loss function while introducing critical new variables, specifically accounting for the losses generated by incomplete financial markets and heterogeneous labor wedges. This analytical breakthrough allows researchers to dissect how monetary policy transmits through an economy populated by households with vastly different marginal propensities to consume, varying levels of liquid wealth, and distinct labor market exposures.

Main Facts and Analytical Framework

At the core of the study is a departure from how central banks traditionally weigh inflation against economic output. In a standard representative-agent model, policymakers balance inflation stabilization with output-gap stabilization to maximize a homogeneous representative utility function. When applied to a HANK economy where household heterogeneity is explicitly modeled, the nature of optimal monetary policy changes dramatically.

The research demonstrates that optimal monetary policy can be decomposed into two distinct components: a time-dependent component and a state-contingent component. The behavior and efficacy of these components depend entirely on the distribution of labor wedges across the population. When labor wedges are homogeneous—meaning market distortions affect all workers equally—monetary policy is structurally incapable of improving household insurance. Under this specific condition, the time-dependent component drops to zero, and the optimal monetary policy perfectly aligns with the traditional representative-agent New Keynesian benchmark.

However, when labor wedges are heterogeneous, significant departures from the representative-agent benchmark emerge. In these scenarios, the time-dependent component of monetary policy acts as a temporary mechanism to alleviate incomplete-market distortions, though it ultimately vanishes over time as the economy adjusts. Meanwhile, the state-contingent component addresses a traditional dual-mandate problem similar to the one found in standard models, but with a crucial modification: it places a substantially higher weight on output-gap stabilization relative to inflation stabilization. Through rigorous calibration of their economic model, the authors discovered that heterogeneous labor wedges raise the optimal weight on output-gap stabilization by approximately 37 percent compared to standard frameworks.

Chronology and Research Evolution

The release of Working Paper 35967 represents the culmination of more than a decade of methodological evolution in macroeconomics. Following the 2008 global financial crisis and the subsequent sluggish recoveries, academic economists increasingly criticized standard representative-agent models for failing to capture the nuances of household debt, wealth inequality, and the uneven transmission of monetary policy.

Between 2010 and 2020, researchers developed the foundational architecture of HANK models, incorporating rich microeconomic data into macroeconomic general equilibrium frameworks. Despite these advancements, determining optimal monetary policy within these complex models remained an elusive mathematical challenge due to the infinite-dimensional nature of wealth distributions.

By October 2026, advances in perturbation methods and linear-quadratic approximation techniques allowed economists to finally solve for optimal policy without resorting to purely numerical simulations that obscure underlying economic mechanisms. The publication of Working Paper 35967 in October 2026 marks a watershed moment, bridging the gap between rigorous theoretical welfare economics and the practical realities of policy design in unequal economies.

Supporting Data and Quantitative Findings

The empirical and quantitative implications of the HANK model detailed in the October 2026 working paper offer striking insights for central banking institutions. Through detailed numerical calibration matching modern economic data, the researchers quantified the exact trade-offs facing policymakers.

Key quantitative findings from the study include:

• A 37 percent increase in the optimal weight assigned to output-gap stabilization relative to inflation stabilization when heterogeneous labor wedges are introduced into the quadratic loss function.
• The complete neutralization of the time-dependent policy component in economies with homogeneous labor wedges, proving that monetary policy alone cannot serve as an effective redistribution tool unless structural labor market distortions vary across households.
• The discovery that a modified dual mandate—one that simply incorporates the higher output-gap weight—manages to achieve nearly all of the aggregate-surplus gains generated by the full, highly complex optimal policy.
• The elimination of the need for explicit, distortionary compensatory fiscal transfers between economic winners and losers, as the adjusted monetary stance implicitly optimizes joint surplus.

These figures challenge the aggressive inflation-targeting orthodoxy that dominated central banking throughout the late twentieth and early twenty-first centuries. By demonstrating that inequality-induced labor wedges demand a more aggressive defense of economic output, the paper provides a quantitative justification for central banks to adopt more flexible reaction functions during downturns.

Official Responses and Expert Reactions

Although central banks have been cautious in formally revising their operational frameworks, academic economists and policy analysts have responded enthusiastically to the publication of DOI 10.3386/w35967. Monetary economists note that the paper provides a mathematically rigorous foundation for what many central bankers have intuitively felt for years: that severe economic inequality alters the transmission mechanism of interest rate policy.

Prominent macroeconomists speaking at academic seminars following the October 2026 release highlighted the practical appeal of the paper’s policy recommendations. Because the research shows that a simple dual mandate with an elevated output-gap weight can capture almost all potential welfare gains, central banks would not necessarily need to invent radical new policy tools or coordinate complex wealth-transfer schemes with fiscal authorities. Instead, existing reaction functions can be recalibrated to account for the distributional frictions highlighted in the HANK framework.

At the same time, central banking traditionalists have urged caution. Critics of expanding central bank mandates argue that shifting greater weight toward output stabilization could risk unmooring long-term inflation expectations, particularly in environments marked by persistent supply-side shocks. Nevertheless, proponents of the HANK approach counter that ignoring household heterogeneity introduces systematic errors into policy decisions, ultimately undermining both price stability and macroeconomic resilience.

Broader Economic Impact and Future Implications

The publication of this working paper arrives at a critical juncture for global monetary policy. As central banks navigate the post-pandemic economic landscape, persistent wealth gaps, and shifting labor market dynamics, the traditional tools of monetary governance face unprecedented scrutiny.

The implications of Working Paper 35967 extend far beyond academic theory, offering actionable insights for institutional design. By proving that incomplete markets and heterogeneous labor wedges systematically alter the optimal trade-offs of monetary policy, the research provides a roadmap for modernizing central bank mandates.

Furthermore, the finding that a straightforward adjustment to output-gap weighting can achieve the vast majority of aggregate-surplus gains simplifies the potential path toward implementation. Policymakers do not need to abandon the familiar framework of dual-mandate management; rather, they must recognize that the numerical weights assigned to employment and output must reflect the unequal realities of modern labor markets.

As central banks worldwide continue to review their monetary policy strategies, frameworks like the one detailed in October 2026 will undoubtedly shape the debate. By bridging the gap between microeconomic inequality and macroeconomic stabilization, this research ensures that the next generation of monetary policy will be better equipped to address the complexities of heterogeneous economies.