High dividend yields can be a warning sign for investors. Yields generally correlate negatively with stock price movements, after all, so higher yields often reflect a business' underperformance and investors' lack of confidence in its rebound potential. One popular tactic that investors use in an attempt to minimize those risks is to focus on high-quality companies that might just be going through rough patches.
The S&P 500 has gained an impressive 35% over the past year. Because of that, its dividend yield has fallen from 1.7% a year ago to around 1.2% these days. To put that into a more tangible context, a $10,000 investment made in the S&P 500 right now would only produce about $120 of dividend income over the next year.