Buy and Sell at the Same Time
Puzzle 4 of National Crossword Day Hard Pack
Question is: Buy and Sell at the Same Time
and the answer is: ARBITRAGE
Word Meaning:
ARBITRAGE — (finance) A market activity in which a security, commodity, currency or other tradable item is bought in one market and sold simultaneously in another, in order to profit from price differences between the markets.
Definitions from Wiktionary.