THE BIG PICTURE · 5,000 SIMULATIONS
5,000 futures. One comparison.
Every strategy gets the same money and the same market in each simulation. Compare typical results, the range of outcomes, and the advantage over investing immediately.
Running 5,000 simulated markets…
How much could you end up with?
Bars span the 10th–90th percentile of ending wealth. The dot is the median; outcomes can fall outside these ranges.
HEAD TO HEAD
Does waiting pay off?
Each bar counts simulations with a similar advantage over lump sum. Left of zero means less ending wealth; right means more. The same market path is used for each comparison.
Fixed random seeds make links reproducible. More simulations reduce sampling noise, not model uncertainty. These are model frequencies, not historical odds or forecasts. The example market below does not change these results.
EXPLORE ONE EXAMPLE
What a single journey looks like
Portfolio value includes invested money + remaining cash. Drag the timeline or move across the chart to compare a month.
SAME ROAD, DIFFERENT RIDES
Change the market story
KNOW WHAT YOU’RE COMPARING
The rules of this experiment
All three strategies get the same starting cash and new savings. Nothing borrows money or sees future prices.
Download monthly results ↓Lump sum
Invest all starting cash immediately.
DCA
Invest equal portions of starting cash at the beginning of each month during the deployment window.
Weighted DCA
Multiply the regular purchase by 1 + sensitivity × decline from the highest total-return index level observed so far. A 20% dip at sensitivity 5 means a 2× purchase. Purchases are capped by available cash; any remaining cash is invested at the final scheduled purchase.
A fair cash comparison
Uninvested cash earns the selected yield. New savings are invested immediately by all three strategies, starting in month 2; there is no deposit at the ending valuation. The dip rule applies to starting cash only. After deployment, all three simply hold.
A model, with limits
Random paths use independent normally distributed monthly log returns. They do not capture every real market risk. No taxes, fees, or trading costs. Inflation is constant. “Today’s dollars” discounts every valuation for inflation. Illustrative education, not investment advice or a historical S&P 500 backtest.
Read more: Investor.gov on DCA · Vanguard’s comparison