go through the floor
From Longman Dictionary of Contemporary Englishgo through the floorgo through the floorBFCHEAPif a price, amount etc goes through the floor, it becomes very low OPP go through the roof Share prices have gone through the floor. → floorExamples from the Corpusgo through the floor• In the past few years, stock prices have gone through the floor.• Last year, sales went through the floor.