The Macroeconomic Impact of Sustainable Investing (Working Paper)

We investigate the impact of sustainable investing—the investing practice that accounts for environmental/societal/governance factors—in a macroeconomic model with dynamic general equilibrium forces. Preference-driven sustainable investing impacts firms’ cost of capital and investors’ saving incentives, resulting in a dynamic feedback loop between productive capital reallocation and investor wealth ownership. We investigate the magnitude and timing of the impact in a calibrated quantitative model where sustainable preferences are disciplined by estimated portfolio return differentials. We finally present a policy implementation exercise that highlights the potential and the limits of sustainable investing as a market-driven mechanism to deliver policy-relevant macroeconomic impact.

September 2026 · Xintong Li and Giacomo Rondina

The Economics of Orbit Use: Open Access, External Costs, and Runaway Debris Growth (Journal of the Association of Environmental and Resource Economists, 2025)

In this paper, we study the economics of satellite launches to understand the impact of the collision risk externality on the dynamics of orbit use. We show that autocatalytic debris growth may render Earth’s orbit unusable, an outcome known as Kessler Syndrome. In our benchmark calibration, Kessler Syndrome can emerge anytime between the year 2040 and the year 2184,

March 2025 · Akhil Rao and Giacomo Rondina

Information Aggregation Bias and Samuelson's Dictum (Journal of Money, Credit and Banking, 2023)

In this paper, using firm-level data from CRSP, we document empirically that stock prices can simultaneously display “microefficiency” and “macroinefficiency;” an idea accredited to Paul Samuelson. To investigate the source of our empirical findings, we propose a theory of aggregation bias based on incomplete information and segmented markets.

August 2023 · Yongok Choi, Giacomo Rondina and Todd B. Walker

Equivalence Results with Endogenous Signal Extraction (Working Paper)

In this paper, we show that dynamic models with dispersed information can be equivalently represented as models with hierarchical information. The result is useful because models with hierarchical information are easier to solve analytically.

May 2023 · Giacomo Rondina and Todd B. Walker

Confounding Dynamics (Journal of Economic Theory, 2021)

In this paper, we establish and characterize a novel propagation mechanism under rational expectations, which we term confounding dynamics, that is responsible for the persistence of imperfect information across economic agents over time on relevant economic variables even when equilibrium variables are observed.

September 2021 · Giacomo Rondina and Todd B. Walker

Learning and Informational Stability of Dynamic REE with Incomplete Information (Review of Economic Dynamics, 2016)

Small changes in agents’ information can produce very different rational expectations equilibria. We show that equilibria preserving incomplete information are informationally stable and learnable, while those fully revealing the underlying shocks are not.

July 2016 · Giacomo Rondina and Todd B. Walker

Financial Prices and Information Acquisition in Large Cournot Markets (Journal of Economic Theory, 2015)

In a large Cournot market, firms’ output decisions are strategic substitutes but their information acquisition can be complementary. The reversal arises because better-informed firms make the financial asset price less informative.

July 2015 · Giacomo Rondina and Myungkyu Shim

Design Limits and Dynamic Policy Analysis (Journal of Economic Dynamics and Control, 2013)

Stabilization policies can reduce volatility at some frequencies while increasing it at others. We characterize these design limits in systems with rational expectations and apply the results to monetary policy rules.

December 2013 · William A. Brock, Steven N. Durlauf, and Giacomo Rondina

A Note on Futia (1981)’s Non-Existence Pathology of Rational Expectations Equilibria (Economics Letters, 2013)

We resolve Futia’s apparent non-existence of rational expectations equilibria with endogenous signal extraction. Accounting for agents’ knowledge of the model reveals an equilibrium identical to the Full Communication equilibrium.

August 2013 · Giacomo Rondina and Todd B. Walker

Nonlinearities in Growth: From Evidence to Policy (Journal of Macroeconomics, 2012)

We examine how evidence of nonlinear growth can inform policy and develop methods for evaluating alternative policies. Applied to foreign aid, the results reject the recommendation to allocate more aid to countries with higher policy quality.

March 2012 · Ethan B. Cohen-Cole, Steven N. Durlauf, and Giacomo Rondina

Frequency-Specific Effects of Stabilization Policies (American Economic Review: Papers & Proceedings, 2008)

Stabilization policies face tradeoffs across frequencies: reducing volatility at one horizon can increase it at another. We show how these design limits depend on forward-looking behavior and affect the evaluation of policy rules.

May 2008 · William A. Brock, Steven N. Durlauf, and Giacomo Rondina

Simple versus Optimal Rules as Guides to Policy (Journal of Monetary Economics, 2007)

We compare simple feedback rules with model-specific optimal rules under uncertainty about the economy and policymakers’ objectives. Examining outcomes at different frequencies shows why the case for optimal rules can break down.

July 2007 · William A. Brock, Steven N. Durlauf, James M. Nason, and Giacomo Rondina