Time-Consistent Portfolio Choice with Changing Investor Preferences

Summary

This article explains time inconsistency in investment decisions: a plan that appears optimal today may no longer suit the investor later as circumstances or preferences change. It contrasts rigid pre-commitment with a dynamic equilibrium strategy designed to account for how future selves may revise their choices. The discussion focuses on portfolio risk through time in an incomplete market, where some risks cannot be fully hedged by trading the available assets.

The article reports that a numerical study finds risk-asset allocation can rise slightly near the investment horizon when two risk sources are independent, while negative correlation can reverse that pattern and lead allocation to decline toward the endpoint. It attributes the result to changing marginal utility of wealth. It also describes a simpler approximate strategy for cases where risk-source correlation is small, reporting a relative allocation error of 0.2% against the exact solution in the simulations. The underlying study is not identified or detailed, and the findings depend on its assumptions and volatility-based risk measure; the article leaves extreme-loss objectives as an open question.

Key ideas

• Time inconsistency arises when an investor's future preferences may differ from the preferences behind today's plan.
• A dynamic equilibrium strategy aims to anticipate future revisions rather than rely only on rigid pre-commitment.
• The reported optimal risk allocation near the horizon depends on the correlation between risk sources.
• The article presents a simpler approximate allocation rule for settings with small correlations and reports close agreement in simulations.
• The results are model-based and use volatility as the risk measure, leaving extreme-loss preferences unresolved.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.