Auction Lab

Where does it settle?

Not what happens at these bids — what happens at every other bid too. The reply curves say whether anyone still has a reason to move.

Run with First-price sealed bid. The link below sweeps every bid, not just these ones, and reports the profile nobody wants to leave. Here is what happens at the bids as typed.

BidderWorth to themBid
A9060
B7050

Step by step

  1. collect bids Each bidder submits one sealed bid; private values are never revealed.
  2. sort Bids are ranked from highest to lowest. Equal bids keep the order the bidders were listed in, so a tie goes to the first-listed bidder.
    60 >= 50
  3. pick winner The highest eligible bid wins the item.
    argmax b_i = A at 60
  4. price rule The winner pays exactly what they bid, so every unit of bid above the runner-up is money left on the table. That is why bidders shade their bids below their true value here, and why the bids you see are not values.
    p = b_i = 60
  5. payments A pays their own bid of 60; the losers pay nothing.
    revenue = 60

How it came out

WinnerA
Price paid by the winner60
Seller revenue60
Value created90
Went to whoever valued it mostyes
BidderPaidEnded up with
A6030
B00

Open this example in the walkthrough

The link carries the whole setup, so you can change a bid and watch what moves — and send the result to somebody else.

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