The optimal strategy for a bidder in a private-values Vickrey auction is to bid his true valuation.

Private-Values

The individual valuation of an item or asset that varies from person to person, usually in the context of auctions or bidding scenarios.

Vickrey Auction

A type of sealed-bid auction where bidders submit written bids without knowing the bid of the other people in the auction and the highest bidder wins, but the price paid is the second-highest bid.

True Valuation

The actual worth of a good or service to an individual, reflecting the maximum amount they are willing to pay to acquire it.