hot money

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Money that is moved by its owner quickly from one form of investment to another, as to take advantage of changing international exchange rates or gain high short-term returns on investments.

Wiktionary

1. n. money, or other financial instruments, that move regularly between different markets in search of the best interest rates
2. n. stolen currency that can be easily traced via serial numbers
3. n. the largest total of money staked on a race etc