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Cognitive Bias Cards
Cognitive Bias Cards · Card 7

Sunk Cost Fallacy

Money or effort already spent is gone either way — the only real question is what to do from here, not what you've already put in.

Money Already Gone
Spent — can't be undone

Irrelevant to what to do next.

The Real Question
What's the right call from today?
In Practice

Holding a losing stock because "I've already put ₹50,000 into it" ignores that the ₹50,000 is gone regardless — the only real question is whether to hold it from today forward.

Generic Example

Finishing a bad movie "because I already paid for the ticket" doesn't get the money back — it just adds two wasted hours to the wasted money.

If I were deciding this fresh today, with no history, what would I actually choose?