Dollar-cost average by investing the same amount every period regardless of market conditions

Buy more shares when prices are low and fewer when high — automatically, without timing decisions.

Why it works

Fixed-amount contributions buy more shares when prices fall and fewer when they rise, which mechanically lowers the average cost per share over time compared to lump-sum buying at random intervals. More importantly, it removes the market-timing impulse: the decision "should I invest right now?" is answered in advance by the automation, bypassing the emotional volatility that causes most investors to sell low and buy high.

How to do it

1. Set a fixed contribution amount on a fixed schedule — weekly, biweekly, or monthly.
2. Do not change the amount based on market news, portfolio performance, or economic forecasts.
3. Treat a market drop as a mechanical buying opportunity, not a signal to pause contributions.

Evidence

Dollar-cost averaging does not maximize expected return in rising markets compared to lump-sum investing, but it consistently outperforms the return that emotional, timing-based investors actually achieve. The behavioral benefit — removing timing decisions — is the primary value. (observational)

Lump-sum investing outperforms DCA in backtests about two-thirds of the time in rising markets; DCA’s advantage is behavioral, not mathematical, for investors with access to a lump sum.

Sources

• DALBAR Quantitative Analysis of Investor Behavior (annual reports) — documents the gap between fund returns and investor returns caused by timing behavior

Common mistake

Pausing contributions during market downturns — exactly when DCA is most powerful — because the falling portfolio feels like evidence that the strategy is broken.