MarketsClassroom · multi-user
Common-Value Auction — The Winner's Curse
An item has one unknown value; everyone gets a noisy hint and bids. The highest bidder wins — and often overpays. A vivid lesson in overconfidence.
You’ll learn: See why the winner of a common-value auction is usually the one who overestimated it — so winning bids systematically overpay.
- Winner's curse
- Judgment under uncertainty
- Overbidding
- Bid shading
Teacher guide
Students will learn to
- Estimate an uncertain value from a noisy private signal.
- Discover the winner's curse: winning means you were probably the most over-optimistic bidder.
- Learn why rational bidders shade their bids below their signal.
Before the session — ask
- If your hint of the value is 120, how much would you bid — and why?
- Among everyone bidding, whose hint is likely the highest? What does that imply for the winner?
After the session — discuss
- Did the winning bid end up above or below the true value? Who 'won'?
- Why should you bid less than your signal in this kind of auction?
- Where do real bidding wars (IPOs, takeovers, oil leases) show this same curse?
Timing
- Briefing & signals3–5 min
- Sealed bids3–5 min
- Reveal & discussion8–10 min
Run it with your class
Students join with a code or QR — no account needed. Teachers start a session from the dashboard.