hot money

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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