A Theory of Saving under Risk Preference Dynamics

Fuente: arXiv
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Main Authors: Ma, Qingyin, Song, Xinxi, Toda, Alexis Akira
Format: Preprint
Published: 2025
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author Ma, Qingyin
Song, Xinxi
Toda, Alexis Akira
author_facet Ma, Qingyin
Song, Xinxi
Toda, Alexis Akira
contents Empirical evidence shows that wealthy households have substantially higher saving rates and markedly lower marginal propensity to consume (MPC) than other groups. Existing theory cannot account for this pattern unless under restrictive assumptions on returns, discounting, and preferences. This paper develops a general theory of optimal savings with preference shocks, allowing risk aversion to vary across states and over time, and shows that incorporating such heterogeneity in risk attitudes fundamentally reshapes the asymptotic dynamics of consumption and saving. In particular, zero asymptotic MPCs (100% asymptotic saving rates) arise under markedly weaker conditions than in existing theory. Strikingly, such outcomes occur whenever there is a positive probability that agents become less risk averse in the future. Therefore, the vanishing MPC emerges as a generic feature rather than a knife-edge result of the optimal savings model, offering a more theoretically robust and empirically consistent account of the saving behavior of wealthy households.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03142
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Theory of Saving under Risk Preference Dynamics
Ma, Qingyin
Song, Xinxi
Toda, Alexis Akira
Theoretical Economics
Optimization and Control
Empirical evidence shows that wealthy households have substantially higher saving rates and markedly lower marginal propensity to consume (MPC) than other groups. Existing theory cannot account for this pattern unless under restrictive assumptions on returns, discounting, and preferences. This paper develops a general theory of optimal savings with preference shocks, allowing risk aversion to vary across states and over time, and shows that incorporating such heterogeneity in risk attitudes fundamentally reshapes the asymptotic dynamics of consumption and saving. In particular, zero asymptotic MPCs (100% asymptotic saving rates) arise under markedly weaker conditions than in existing theory. Strikingly, such outcomes occur whenever there is a positive probability that agents become less risk averse in the future. Therefore, the vanishing MPC emerges as a generic feature rather than a knife-edge result of the optimal savings model, offering a more theoretically robust and empirically consistent account of the saving behavior of wealthy households.
title A Theory of Saving under Risk Preference Dynamics
topic Theoretical Economics
Optimization and Control
url https://arxiv.org/abs/2511.03142