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)
Further reading
If you speak a second or third language, you may remember the first time you dreamed in that new tongue. But does this milestone mean you’re actually fluent? And a couple’s dispute over the word regret: Say you wish you’d been able...
While reading Great Expectations (Bookshop|Amazon) by Charles Dickens, a listener in Arlington, Texas, is surprised when one of the characters inherits some money, which Dickens describes as a cool four thousand. Were they really using cool that way...