When a stock's dividend yield looks high, what would make you suspect the payout is at risk?

A high dividend yield often reads as a bargain signal, but the yield is just the annual dividend divided by the current price. When the price falls sharply, the yield rises mechanically, so a big number can reflect a problem rather than generosity. The useful question is whether the payout is covered by cash flow, not by the headline yield. Some checks worth thinking through: free cash flow relative to total dividends paid, the payout ratio measured against earnings and against cash, and whether the company has been funding distributions with new debt or asset sales. Payout history matters too. A long record of raises looks different from a recent cut, and a company that has already reduced its dividend once may be more likely to do it again under stress. The counterargument is that a high yield can also be correct, since markets sometimes overreact and a payout can be safe even when the stock looks distressed. So the test is not whether the yield is high but what specific evidence would tell you the market has it wrong. What single metric do you rely on first when you check whether a dividend is actually sustainable?