The VIX (CBOE Volatility Index) measures the market's expectation of 30-day volatility on the S&P 500. It's often called the "fear gauge" — when markets are calm, VIX is low. When uncertainty spikes, VIX rises.
Option premiums are directly tied to implied volatility. When VIX is high, the puts you sell are worth more — you collect larger premiums. When VIX is low, premiums shrink and the same strategy generates less income.
This doesn't mean you should only sell puts when VIX is high. The elevated VIX exists because risk is genuinely higher. The art is finding the balance — enough volatility for worthwhile premiums, but not so much that the market is in free fall.
ThetaLoop's Theta Compass uses VIX as one of three core inputs (alongside market breadth and SPY regime). A moderate, falling VIX is scored favorably — it suggests fear is subsiding and conditions are stabilizing, while premiums are still elevated from the recent uncertainty.