leave money on the table
v. phr.— «The difference between what the high bidder on a lease parcel offers and the bid of his nearest competitor is called in the industry “leaving money on the table.” Humble left the table well laden on several of its bids.» —“Record $603 Million Bid for Santa Barbara Oil Leases” by Thomas W. Bush Los Angeles Times Feb. 7, 1968. (source: Double-Tongued Dictionary)