Options-implied borrow
SentimentAdvanced
A synthetic short in the options market, long a put and short a call at the same strike, embeds a borrow rate. Cboe's borrow-intensity series summarizes that implied lending rate across many stocks. Research has asked whether day-to-day changes in aggregate borrow intensity line up with the next move in the broad market. It is a positioning gauge derived from option prices, not a stock tip.
Not investment advice. Nothing here is a recommendation to buy or sell anything. Backtests and historical studies are not guarantees, and a rule that worked in one sample can fail in the next. Trading can lose money. Links are for education, not endorsements. Do your own research.
- Rules
- Observe the published aggregate borrow-intensity change at the close. A stated rule is long the broad equity market the next session after a rise in borrow intensity and flat or short after a fall, with a one-day hold. Use the series as published that day. Do not compute a personal 'borrow' from stale option quotes and call it the same signal.
- Where AI fits
- AI can align the vendor series to the close without filling missing days from the future, and it can test a one-day hold with realistic index costs. It should not retune the holding period across the same crisis it uses as proof. If the options quotes are wrong, the intensity number is wrong.
- Markets
- A broad U.S. equity index as the trading vehicle. The input is an aggregate of single-stock option-implied borrow.
- Timeframes
- One-day hold after the daily print.
- Risks
- Implied borrow is noisy, model-dependent, and sensitive to bad option quotes. A one-day pattern can be a microstructure artifact. Crises dominate the results of any short sample. This is not a signal to copy a short seller in a single name.