Rupee cost averaging

Investing a fixed amount at regular intervals, which buys more units when prices are low and fewer when they are high.

Three monthly investments of ₹10,000 at unit prices of ₹100, ₹125 and ₹80 buy 100, 80 and 125 units, an average cost of ₹98.36 against a simple average price of ₹101.67.

Its arithmetic advantage is real and small. Its behavioural advantage is large, because the method removes the decision that investors most reliably get wrong.

It does have a cost. Against a lump sum in a rising market it underperforms.