A controversial concept, often used by politicians to justify imposing a tax on profit that in theory is earned unexpectedly, through circumstances beyond the control of the company concerned, and is thus deemed undeserved and ripe for the taking by the tax authorities. As the profits were neither expected nor a result of the efforts of the firm, taxing them should not harm the firm’s incentives to maximize future profits. The problem comes when greedy politicians start claiming that profits are windfalls when in fact they are deserved and expected. Then taxing them sends a signal to firms that they should not try too hard to make profits, as if they do too well they will not get to keep the profits anyway. If this became widely believed, effort would probably decline and economic growth would be slower.