make (or lose or spend) money hand over fist make (or lose or spend) money very rapidly or in very large quantities. informal

☞ This phrase first appeared in the mid 18th century as hand over hand. Found in nautical contexts, it referred to the movement of a person's hands when rapidly climbing a rope or hauling it in. By the mid 19th century, hand over hand was being used to mean 'advancing continuously and rapidly', especially of one ship pursuing another. Hand over fist is first recorded in the early 19th century, also in a nautical context, but it was soon used more generally to indicate speed, especially in the handling of money.

2013Eric S. RaymondArmed & Dangerous It doesn't matter that Android is now the #1-selling smartphone in the U.S. and worldwide, Apple is making money hand over fist.