Dollar-cost averaging vs. lump sum

If you suddenly have a large sum to invest — a bonus, an inheritance, a sale — should you put it all in at once, or spread it out over several months?

What the historical data tends to show

Because markets rise more often than they fall over long periods, investing the full amount immediately has historically outperformed spreading it out roughly two-thirds of the time when studied over rolling multi-decade windows. The logic is simple: more time invested generally means more time compounding.

Why people still spread it out

Dollar-cost averaging isn't really a performance strategy — it's a regret-minimization strategy. Investing a lump sum right before a downturn is psychologically harder to sit through than seeing the same downturn happen gradually across several smaller purchases. For some investors, avoiding the scenario where they panic-sell after a bad lump-sum entry point is worth a statistically lower expected return.

A middle-ground approach

Some investors split the difference: investing a portion immediately and spreading the rest across three to six months. This captures some of the time-in-market advantage while reducing the single worst-case entry point.

The one case where spreading out clearly helps

If the money is needed within a short, defined window (a house down payment in 18 months, for example), neither approach is really about maximizing returns — that money likely shouldn't be fully invested in volatile assets in the first place, regardless of entry strategy.