Asset Allocation by Age: The 100-Minus-Age Rule and Its Limits

Asset allocation is the decision that matters more than which specific fund you pick — how your money is split between equity, debt, gold, and cash. Most of what determines your returns over the long run comes from this split, not from finding the “best” mutual fund inside it.

The 100-minus-age rule

The most common starting point in India is simple: subtract your age from 100, and that’s roughly the percentage to hold in equity. A 30-year-old lands around 70% equity, 30% debt and other assets. A 60-year-old lands closer to 40% equity. The logic is straightforward — younger investors have more time to recover from a bad market, so they can afford more volatility for a better long-run return; the allocation shifts toward safety as retirement gets closer.

It’s a rule of thumb, not a formula to follow blindly. A 35-year-old with an irregular freelance income has a different risk capacity than a 35-year-old with a stable government job, even though the rule gives them the same number.

The rule that matters more: allocate by time, not just age

Age-based allocation makes sense for money you won’t need for a long time — a retirement corpus, for instance. It makes much less sense for a goal with a fixed date attached. The horizon of the specific goal should usually override your age:

• Under 3 years away — mostly debt and cash. A market downturn with no time to recover is a real risk to a goal this close.
• 3 to 7 years away — a balanced or hybrid mix, some equity, enough debt to cushion a bad few years.
• 7+ years away — age-based equity allocation is reasonable, since there’s time to ride out volatility.

This is why a single household usually needs more than one allocation, not one. A 30-year-old’s retirement money and their 2-year home-down-payment fund shouldn’t be invested the same way, even though the 100-minus-age rule would suggest otherwise for both.

Rebalancing is the part people skip

An allocation set once and never revisited drifts on its own — a strong equity market can quietly push a 70/30 split to 80/20 within a couple of years, taking on more risk than originally intended without a single active decision. Checking allocation against target periodically, and adjusting either the mix or the goal’s timeline, is the maintenance work that makes the initial decision keep meaning something.