Matias Bayas-Erazo

Economist working on macroeconomics and public finance.

I am a Postdoctoral Researcher at the University of Zürich. My research focuses on macroeconomics and public finance. I use theory and computational tools to identify new mechanisms and quantify their impact. I’m also curious about AI and its applications to research and beyond.

I received my Ph.D. in Economics from Northwestern University in 2024.

Now Wrapping up paper on optimal commodity taxation with inattention. Solving for optimal transitions in sequence space. Building ARDE, an environment for autonomous research in hard-to-verify domains. Training for a half marathon. Reading about agentic RL and trying to get through Brothers Karamazov.

Matias Bayas-Erazo

Research

Working Papers

  • Fiscal policy choices affect both the degree of progressivity of the tax system and the amount of public debt in circulation. What is the connection between these two elements? In this paper, I consider a benevolent optimizing government and explore how both progressivity and indebtedness depend on the government’s preferences for redistribution. Somewhat surprisingly, I show that differences in preferences for redistribution lead to a negative correlation between progressivity and indebtedness, as a planner that cares more for redistribution favors lower levels of public debt.
  • Models of lumpy capital adjustment are too responsive to interest rates relative to empirical evidence. We argue that allowing for small convex adjustment costs in labour can help these models better match the data. Convex costs cause labour to increase slowly in response to a shock thus smoothing out the impact on the marginal product of capital. Due to both depreciation and uncertainty over future productivity, this delay in the benefits of additional capital can have a large impact on the responsiveness of capital investment.
  • We use a simple model to study the effects of tariffs on the current account balance when a country runs permanent trade deficits. The model features a country that supplies a liquid asset to the rest of the world, which allows the country to run a permanent and sustainable current account deficit. Unlike in models based on the traditional intertemporal approach, tariffs do not affect saving through their effects on real interest rates, and have muted effects on the current account balance. We also show how shifts in liquidity demand and taxes on world liquidity can be interpreted from a trade-policy perspective.
  • We study optimal commodity taxation in economies with inattentive consumers. In our setting, consumers may make both random and systematic mistakes relative to the frictionless benchmark; they may allocate attention differently across markets; they may exhibit behavior akin to sparsity or mental accounting. Inattention is however rational (Sims, 2003). This delivers an irrelevance result — optimal taxes may satisfy the same sufficient-statistics formulas as those in classical public finance (Ramsey, 1927; Diamond and Mirrlees, 1971b; Diamond, 1975). Put simply, a benevolent Ramsey planner should not care whether agents are inattentive or what’s “under the hood” of the observed market-level demands. We discuss the conditions that sustain this result, its possible violations, and its relation to behavioral public finance.
  • We introduce ARDE (Agentic Research Development Environment), a modular, open-source environment for autonomous research. ARDE has three main building blocks – a minimal agentic loop that coordinates models and execution; skills that structure research into tasks with clear inputs, outputs, and success criteria; and pluggable orchestration that arranges skills into workflows. This architecture lets ARDE treat research as a search problem over skills, exploring sequences of tasks, evaluating each step, and deciding whether to continue, branch, or backtrack. We apply ARDE to economic research and show that the same pipeline generalizes across problem classes. We release the complete system along with ARDE-Bench, an open evaluation for AI reasoning in hard-to-verify research tasks.
  • Policy/Book Chapters

  • Understanding Ecuador’s Growth Prospects
    In Assessing the Left Turn in Ecuador, F. Sánchez & S. Pachano (Eds.) (2020)
    This chapter sheds some light on the prospects for the Ecuadorian economy in the aftermath of the Revolución Ciudadana and a permanent reduction in oil prices. Given that the economy’s progress is contingent on whether or not private sector investment can take over and replace the public sector as the main engine of the economy, I have focused on how fiscal policy can affect private investment decisions. So, this analysis relates to the importance of solving the implementation problem in order to ensure that the economy moves toward a period of growth and increasing living standards. Whether fiscal authorities manage to construct a credible and strategic fiscal policy will determine the economic outcomes to be realized in the future. Moreover, given that individual preferences may not be separable from government expenditures, the need to create a fiscal stabilization fund has been emphasized, as well as the importance of focusing adjustments on current rather than capital expenditures.
  • Code & Notes

    ECON

  • Deep RL for solving heterogeneous agent economic models.
  • Time series econometrics toolkit for mixed-frequency VAR analysis.
  • Julia library for dynamic economic models.
  • AI

  • 2025
    LLM-powered tool for automated literature review.
  • AI-powered training planner for endurance athletes.
  • Notes

  • Notes on heterogeneous agent New Keynesian models.