Key Takeaway: The put/call ratio measures how many put options are being bought relative to calls. Extreme high readings (lots of put buying) are often contrarian bullish signals — when everyone is hedging, the worst is usually already priced in. Extreme low readings can signal complacency ahead of a selloff.
The put/call ratio is simply the number of put options traded divided by the number of call options traded on a given day.
The ratio is available for individual stocks, the broad market (via the CBOE), and specific indices like SPX.
The put/call ratio is most useful at extremes, and it works because of how retail sentiment works. When retail traders pile into puts, it's often near a bottom — they've finally capitulated to fear. When calls are all everyone buys, the bullish thesis is already fully priced in.
High put/call ratio (above 1.2 on equity options): Excessive fear. Often precedes a bounce. The market has already priced in the bad news that everyone is hedging against.
Low put/call ratio (below 0.5): Excessive euphoria. Complacency. Few are hedging, which often precedes a selloff when the unhedged crowd gets caught offside.
This is the same logic as the VIX being a "fear gauge" — extreme readings revert.
Not all put/call ratios are created equal:
CBOE Equity P/C Ratio: Only counts equity options (individual stocks). Normal range is 0.5–0.8. This is the cleanest signal because it strips out index hedges.
CBOE Total P/C Ratio: Includes index options. Index puts are heavily used by institutions for portfolio hedging regardless of sentiment, so this ratio is noisier and skews higher.
CBOE Index P/C Ratio: Only index options. Dominated by institutional hedging — less useful for retail sentiment analysis.
Rule of thumb: Use the equity-only ratio for sentiment signals. Total and index ratios are dominated by professional hedging programs that tell you less about retail crowd psychology.
The put/call ratio is a background indicator, not a timing tool. Here's how to actually apply it:
Confirmation, not entry signal: If you're already bullish based on technicals and the equity P/C ratio spikes above 1.2, that's confirmation your contrarian thesis has fuel. Don't enter just because P/C is high.
Multi-day smoothing: A single day of extreme readings can be noise (one institution executing a large hedge). Use a 5-day or 10-day moving average to see sustained sentiment shifts.
Divergences matter: If the market is selling off but the P/C ratio isn't spiking — meaning people aren't even bothering to hedge — that's a warning sign the selloff has further to go.
Per-stock P/C: For individual tickers, unusual spikes in put volume before earnings or news can signal informed positioning. It's one of the inputs options flow traders watch closely.
The put/call ratio is not a crystal ball. Three important caveats:
Use it as one input alongside price action, IV levels, and the broader macro backdrop.