windfall
noun [ C ]
FINANCE, TAX uk/ˈwɪndfɔːl/ usan amount of money that you receive unexpectedly:
get/have/receive a windfall Investors each received a windfall of $5,000.
cash/financial/tax windfall The investment firm unveiled a cash windfall for shareholders worth up to $650m.
windfall gains/profits Staff stood to make substantial windfall gains from share options.