A sealed-bid auction is an auction process in which all bidders submit sealed bids simultaneously. With sealed-bid auctions, no bidder knows how much the other participants have bid. At the end of the bidding process, all bids are opened at the same time and the highest bidder wins the auction. The term “sealed bid” originally stems from a time when written bids were actually placed in a sealed envelope. While that may still occur in certain situations, it’s now common for sealed-bid auctions to be conducted virtually under the same premise.