Drip Feed vs Lump Sum Investing: Which Strategy Wins?
You've got the lump sum. Your gut says wait. Vanguard ran the maths back to 1976 and the answer isn't the one most cautious investors want to hear.
Vanguard study: lump sum wins (UK market, 1976 onwards)
Source: Vanguard "Cost averaging: invested now or later?" using UK, US and Australian data since 1976.
When each approach makes sense
| Situation | Better choice |
|---|---|
| Sum under 20% of portfolio | Lump sum |
| First significant investment | Drip feed 3 to 6 months |
| Life-changing inheritance | Drip feed 3 to 6 months |
| Markets already down sharply | Lump sum |
| Cannot stomach a 30% drop | Drip feed (or rethink allocation) |
| Sitting in cash deciding | Anything beats this |
The worst option is procrastination, not whichever strategy you pick.
Key takeaways
Lump sum investing wins roughly two-thirds of the time because markets go up more than they go down. The longer you delay putting money to work, the more growth you miss.
Drip feeding (pound-cost averaging) reduces your exposure to short-term crashes. If a 20% drop in month one would keep you awake at night, spreading the investment out is a valid choice.
The best strategy is the one you actually stick with. A perfect plan you abandon after a market dip is worse than a good-enough plan you hold for 20 years.