How to Hedge a Portfolio With Index Puts

Reviewed by Leon Moyer - Published October 9, 2026 - Last reviewed October 9, 2026

To hedge a portfolio with index puts, you buy put options on a broad stock index, or on a fund that tracks one, that your portfolio tends to move with. If the market falls below the put's strike price, the puts gain value and offset the portfolio's loss beyond that point.

It is the portfolio-wide version of a protective put: one position covers the market risk the holdings share. At expiration, the most the hedged portfolio can lose is the drop to the strike plus the premium, its break-even is the starting price plus the premium per share, and its upside stays open, less the premium paid.

How do index puts protect a portfolio?

A put option is the right to sell the underlying at the strike price, 100 shares per contract for a fund, or the same value in cash for an index. A put on an index or index fund gains value as that index falls below the strike. Because most diversified stock portfolios fall when the broad market falls, gains on the puts offset losses on the portfolio.

The protection is only as good as the match between your portfolio and the index. A portfolio of large U.S. companies tracks a broad U.S. index closely. A portfolio of small companies or one sector may not, a gap called basis risk.

How many puts do you need to hedge a portfolio?

Start with beta, a measure of how much a portfolio tends to move when the index moves. A beta of 1.0 means it tends to move about as much as the index, 1.2 means about 20% more, and 0.8 about 20% less. Your broker or portfolio tool may show an estimate; it is based on the past and can drift.

In one sentence: contracts needed = portfolio value x beta ÷ (index or fund price x 100).

A $250,000 portfolio with a beta of 1.2 is hedged like $300,000 of XYZ, and each contract on XYZ at $100 covers $10,000, so the hedge needs 30 contracts. Counts rarely come out whole; rounding down leaves some exposure unhedged, and rounding up adds cost.

Should you use index options or index fund options?

There are two main ways to buy puts on the broad market, and which one fits depends on the size of the portfolio:

• Index options, such as Cboe's S&P 500 Index (SPX) options, are written on the index itself. Per Cboe's SPX product page, they are European style (exercisable only at expiration), settle in cash, and have a $100 multiplier. With the index in the thousands, one contract covers several hundred thousand dollars of stock.
• Index fund options are written on an exchange-traded fund that tracks an index. Per Cboe's equity options specifications and exchange-traded product options page, they generally cover 100 shares, are American style (exercisable on any business day), and settle by delivering shares. Their smaller size makes them easier to match to a modest portfolio.

The lesson SPX vs SPY Options: Index Options vs ETF Options, and XSP covers the differences in depth. The two can also be taxed differently; this course's Tax Treatment of Options module gives an overview, and a tax professional can say what applies to you. Brokers also differ in which of these they allow at each options approval level, and in what they charge.

The hedged line is flat below $90: every further dollar XYZ falls costs the portfolio $1,000 and adds $1,000 to the puts. Above $90 the two lines run parallel, $1,220 apart. That gap is the price of the floor.

How do you choose the strike and expiration?

The strike works like an insurance deductible. A strike close to today's price starts protecting almost at once, but costs more. A strike further below is cheaper, but you absorb the first part of any fall yourself.

At the same model setup (26% implied volatility, 90 days), the 95 put costs $2.54 and the 85 put $0.49. Moving from the 95 strike to the 85 strike cuts the premium for 10 contracts from $2,540 to $490 but raises the worst-case loss from $7,540 to $15,490. Tail hedgers often choose strikes well below the market, to survive a crash rather than avoid every dip.

The expiration is a trade-off too. Longer-dated puts cost more in total but usually less per day of protection, and they give a crash more time to happen while the hedge is in place. How Much Does It Cost to Hedge a Portfolio? works through the numbers.

What can go wrong with an index put hedge?

• The hedge expires first. A put protects only until its expiration. A crash a week later is not covered unless the hedge was rolled into a new one.
• Basis risk. If your portfolio falls more than the index, the puts cover less than you expected. Beta is an estimate, and in a crash it can change.
• The cost adds up. In most quarters the puts expire worthless. That steady cost is the real price of tail protection.
• You do not have to wait for expiration. After a sharp fall, you can sell the puts to lock in their gain. Holding on keeps the protection but risks giving the gain back if the market rebounds.