Should I invest a windfall as a lump sum or dollar-cost average it in?

Mathematically, investing a lump sum all at once beats spreading it out about two-thirds of the time, simply because markets rise more often than they fall and time in the market matters. So if you can stomach it, putting the full amount to work immediately has the higher expected return. But dollar-cost averaging — investing equal slices over, say, 6 to 12 months — is a legitimate choice if the regret of a crash right after a lump sum would rattle you into bad decisions. The best strategy is the one you'll actually stick with. A middle path: invest a big chunk now and average the rest over a few months. Whatever you choose, set a fixed schedule and automate it so emotion doesn't take over. Keep money you need within three years out of stocks regardless.