Stock Market · Mind over Markets

Loss aversion

Loss aversion is the most powerful behavioural bias in investing. Losing ₹10,000 hurts roughly twice as much as gaining ₹10,000 feels good. This asymmetry drives most bad investment decisions.

The original experiment

Kahneman and Tversky offered people two choices:

Choice A: 50% chance to win ₹1,000, 50% chance to win nothing.

Choice B: Guaranteed ₹450.

Most people picked B, even though A has higher expected value (₹500).

Now reverse the framing:

Choice A: 50% chance to LOSE ₹1,000, 50% chance to LOSE nothing.

Choice B: Guaranteed LOSS of ₹450.

Most people picked A. Accepting more uncertainty to AVOID a sure loss.

How loss aversion ruins investing

1. Holding losers too long: 'I'll sell when it gets back to break-even.' Often never happens.

2. Selling winners too early: 'Let me lock in this 10% gain before it disappears.' Misses the 200% run.

3. Avoiding stop losses: 'If I don't acknowledge the loss, it's not real.'

4. Refusing to invest after a loss: 'I lost money in stocks once. Never again.'

> Loss aversion + sunk cost fallacy = the deadly combination that traps investors in declining positions for years.

The math the brain ignores

₹100 invested at 12% becomes ₹965 in 20 years.

₹100 invested at 8% becomes ₹466 in 20 years.

Avoiding 4% extra return (because equity 'feels risky') costs you HALF your final wealth. Loss aversion makes investors choose the lower-return path because it feels safer in the short term.

Defeating loss aversion

1. Pre-commit to stop losses BEFORE entering trades

2. Frame losses as 'cost of doing business', not personal failure

3. Track total portfolio performance, not individual trade outcomes

4. Remember: avoiding small losses creates the conditions for huge losses

Takeaway. Loss aversion: losses hurt 2x as much as equivalent gains feel good. Causes holding losers too long and selling winners too early. Defeat with pre-committed stop losses and tracking total portfolio performance, not individual trades.