Which strategy puts more money in your pocket? Compare investing all at once versus spreading it out over time.
The debate is classic: you have a windfall (inheritance, bonus, savings) and need to invest it. Do you put it all in at once, or spread it out over months to "smooth" your entry price?
You invest the entire amount on day one. All of it starts compounding immediately. The risk: if the market drops right after you invest, you're fully exposed. The reward: if the market rises (which it does most of the time), you captured every point of gain from day one.
You divide the total amount into equal monthly installments and invest one portion each month. Each portion then compounds for the remaining time. You never buy all at the top, but you also never buy all at the bottom — you get an average price.
A 2012 Vanguard study found that lump sum investing outperforms DCA approximately 2/3 of the time across US, UK, and Australian markets. The reason is simple: markets go up more often than they go down. Time in the market beats timing the market.
However, DCA wins in the other 1/3 of scenarios — typically when markets fall significantly right after investment. More importantly, DCA dramatically reduces regret. An investor who DCA'd into a crash sleeps better than one who lump-summed at the peak.
DCA is optimal for behavioral reasons, not mathematical ones. If a market drop right after investing would cause you to panic-sell, DCA preserves your psychology and therefore your portfolio. The "best" strategy is the one you'll actually stick to.
DCA also mirrors how most people actually invest — through regular paycheck contributions to a 401(k). In that context, DCA isn't a choice, it's the mechanism.