From an ethical standpoint, to how much effort must I go to return an overpayment from my employer? I received an overpayment of $10,000 in a summer paycheck (the bonus should have been $10,000 paid over two months at $5,000 each; instead it was two months at $10,000 each). I promptly reported the overpayment to payroll, but several months later, they still haven't done anything about it. I was taxed on the overpayment as income. Is it ethically incumbent upon me to follow up until they take the money back, or is there a point at which it's reasonable for me to keep it?