Trading Is Hazardous to Your Wealth: The Common Stock Investment Performance of Individual Investors
Source: Barber, B. M. & Odean, T. (2000) · Journal of Finance 55(2), 773–806 · DOI 10.1111/0022-1082.00226
TL;DR
Using account-level data for 66,465 households at a large discount broker over 1991–1996, the paper shows that investors who trade the most earn the lowest net returns. Gross returns are similar across investors regardless of trading frequency, but transaction costs from active trading destroy net performance: the most active households earn a net 11.4% annually versus 17.9% for the market. The pattern fits overconfidence, not rational trading — "trading is hazardous to your wealth."
The idea
Individual investors trade far more than a rational expectations view (Grossman–Stiglitz: trade only when marginal benefit ≥ marginal cost) can justify. Overconfidence models (Odean 1998b; Gervais–Odean 1998) instead predict investors trade to their own detriment. The key empirical separation: if trading were informed, frequent traders should earn higher gross returns to offset their costs. They do not. Their gross returns roughly match infrequent traders and the market, so the heavy transaction costs they incur translate directly into net underperformance — a measurable wealth loss tied to a behavioral bias.
Evidence
Sample: position statements and trades for 66,465 households (of ~78,000 in the raw data) at a large discount brokerage firm; six years, February 1991 through January 1997.
Net returns by trading frequency (annualized geometric mean): households that trade most earn 11.4% net; those that trade least earn 18.5% net; the value-weighted NYSE/AMEX/Nasdaq market index returns 17.9%.
Gross vs. net for the average household: gross 18.7% (aggregate 18.2%), essentially matching the market; net 16.4% (aggregate 16.7%) after bid-ask spread and commissions — i.e., underperformance is driven by costs, not stock selection.
Little difference in gross performance between high-turnover households (monthly turnover above 8.8%) and low-turnover households — inconsistent with rational/informed trading.
Trading is heavy: the average household turns over more than 75% of its common-stock portfolio annually; the most active households exceed 250% annual turnover.
Costs are high: the average round-trip trade above $1,000 costs roughly 3% in commissions and 1% in bid-ask spread.
Style tilts: households tilt toward small, high-beta stocks, with a weaker tilt toward value (high book-to-market). Benchmarks include the CAPM and the Fama–French (1993) three-factor model, plus self-selected characteristic-based benchmarks.
Why it matters
Foundational, account-level evidence that overtrading is costly and that overconfidence offers a parsimonious explanation. It is a sober reminder that an apparent gross edge can be entirely consumed by turnover and transaction costs — the same lesson cost-aware backtesting enforces for systematic strategies. The paper helped launch a large behavioral-finance literature on individual investor behavior (e.g., the gender/overconfidence follow-up).
Caveats
One brokerage firm and one period (mid-1990s); the authors believe results generalize but note retail-account behavior may differ, and observations are limited to discount accounts.
It documents the cost of trading, not whether any active strategy could overcome those costs.
Findings concern directly held common stocks, not investors' total wealth or other holdings.
Key references
Barber, B. & Odean, T. (2000) — Trading Is Hazardous to Your Wealth — Journal of Finance
Odean, T. (1999) — Do Investors Trade Too Much? — American Economic Review
Barber, B. & Odean, T. (2001) — Boys Will Be Boys: Gender, Overconfidence, and Common Stock Investment — Quarterly Journal of Economics
Grossman, S. & Stiglitz, J. (1980) — On the Impossibility of Informationally Efficient Markets — American Economic Review
Provenance: verified/generated from the paper's full text.
