The Protective Put: What the Insurance Cost on SPY
A protective put is a put option bought on shares you already own, so that below the strike price every further dollar the shares lose is made back by the put. It works like an insurance policy: the premium is the price, the strike sets the floor, and the expiry date is the end of the cover.
A protective put pairs a stock you hold with a put option on that same stock. The shares keep all of their upside; the put sets a price below which further losses are covered until it expires. You pay for that in advance, and the payment is gone whether or not the cover is ever used.
This page works one through on SPY, the exchange-traded fund that tracks the S&P 500, with the real quotes from 25 Sep 2026, then sets those prices against how often SPY has actually fallen far enough for the cover to pay.
How it works
The pieces. You own 100 shares. You buy one put contract, which covers 100 shares, with a strike price and an expiry date.
- Above the strike at expiry, the put expires worthless. You keep the shares and their gain, less the premium.
- Below the strike at expiry, the put is worth the strike minus the share price. That value rises by one dollar for every dollar the shares fall, so your loss stops growing.
- The worst case is fixed on day one: the purchase price minus the strike, plus the premium, per share.
- The breakeven is the purchase price plus the premium. The shares have to rise by the cost of the put before the combined position is ahead.
Three choices set the price. A strike closer to the current price costs more, because the cover starts sooner. A longer expiry costs more in dollars but usually less per month. And the market’s expected movement, its implied volatility, lifts every premium when it rises.
The name “married put” is used when the shares and the put are bought on the same day. The payoff at expiry is identical; only the order of the purchases differs. The Options Industry Council, the education site of The Options Clearing Corporation, uses the same two names and the same worst case: stock purchase price minus strike plus premium.
A worked example
On 25 Sep 2026, SPY closed at $771.35. Take 100 shares, $77,135 of stock, and one put contract expiring 18 Dec 2026, 84 days out, with a $733 strike, the listed strike nearest to 5% below the close. The quoted ask was $8.69 a share, so the contract cost $869.
The fixed numbers:
- Worst case: ($771.35 - $733 + $8.69) x 100 = $4,704, or 6.10% of the $77,135.
- Breakeven at expiry: $771.35 + $8.69 = $780.04.
- Cost as a share of the position: $869 / $77,135 = 1.13%.
Four prices on 18 Dec 2026:
| SPY at expiry | Shares alone | Put value | Shares + put, after the $869 premium |
|---|---|---|---|
| Down 20%, $617.08 | -$15,427 | $11,592 | -$4,704 |
| Down 10%, $694.22 | -$7,714 | $3,879 | -$4,704 |
| Flat, $771.35 | $0 | $0 | -$869 |
| Up 10%, $848.49 | +$7,714 | $0 | +$6,845 |
Read plainly: in the two falls the combined loss stops at $4,704, however far SPY drops below $733. If SPY finishes flat, the only change is the $869 spent. If it rises 10%, the premium trims the gain from $7,714 to $6,845.
The original data
What the cover cost. Every price below is the quoted ask on the Cboe delayed SPY chain saved at 10:47 pm New York time on 25 Sep 2026, after the close, as a share of the $771.35 close. The expiries are the standard third-Friday monthly dates, and each strike is the listed one nearest to the target. “A year” multiplies the cost by 365 and divides by the calendar days, which is what buying the same cover back to back would add up to at these prices.
| Expiry (days) | At the money ($771 or $770) | 5% below ($733 or $735) | 10% below ($695) |
|---|---|---|---|
| 16 Oct 2026 (21) | 1.02%, 17.69% a year | 0.18%, 3.09% a year | 0.06%, 1.06% a year |
| 18 Dec 2026 (84) | 2.31%, 10.05% a year | 1.13%, 4.90% a year | 0.62%, 2.70% a year |
| 19 Mar 2027 (175) | 3.40%, 7.09% a year | 2.19%, 4.56% a year | 1.39%, 2.90% a year |
| 17 Sep 2027 (357) | 5.15%, 5.26% a year | 3.84%, 3.93% a year | 2.77%, 2.83% a year |
Two patterns stand out. Moving the strike 5% lower roughly halved the three-month cost, from 2.31% to 1.13%. And short cover was the dearest per year: at the money, one month at a time added up to 17.69% a year, while a single one-year put cost 5.26% a year. Every quote is in the SPY put cost table.
What past drops would have paid. Using SPY’s daily closes from 29 Jan 1993 to 25 Sep 2026, price only, every trading day was taken as a start and compared with the close the same number of calendar days later as each expiry. The payout is what a put at that strike would have been worth at expiry, as a share of the starting price. These windows overlap heavily and trace one market’s history, so they describe the past, not the odds for any single quarter.
| Days | Windows | Finished lower | More than 5% lower | More than 10% lower | Average payout, at the money | Average payout, 5% below |
|---|---|---|---|---|---|---|
| 21 | 8,458 | 37.3% | 6.9% | 1.2% | 1.13% | 0.21% |
| 84 | 8,413 | 29.7% | 13.2% | 5.4% | 1.77% | 0.75% |
| 175 | 8,351 | 26.7% | 14.9% | 7.4% | 2.22% | 1.20% |
| 357 | 8,227 | 20.7% | 15.6% | 12.3% | 2.99% | 2.11% |
Set side by side, the longer covers cost more than they paid on average. For 84 days, the put 5% below cost 1.13% against an average past payout of 0.75%; for 357 days, 3.84% against 2.11%. The 21-day puts were the exception: 1.02% against 1.13% at the money, and 0.18% against 0.21% at 5% below. Every window count and payout is in the SPY drop table.
Choosing the strike and the length
The strike decides which losses you keep. A put 5% below leaves the first 5% of any fall with you, plus the premium; a put 10% below leaves the first 10%. That is the same trade-off as the deductible on a car policy.
The length decides how often you pay the spread. The gap between bid and ask on the twelve SPY puts in the first table ran from $0.01 to $0.23 a share, small against the premium. On thinly traded stocks it can be a large part of the price, and rolling monthly pays it twelve times.
The quotes are one day’s prices. Cboe’s 30-day implied volatility for SPY was 11.98% on 25 Sep 2026. When the market is falling that number rises, and every premium in the first table rises with it.
When it fails
It fails as a plan when it is judged on payouts. In 70.3% of past 84-day windows SPY did not finish lower at all, so an at-the-money put bought in those windows expired worthless. That is the expected outcome of insurance, and someone who stops buying after a run of expired puts has not learned anything about the next quarter.
It fails on cost when it is rolled for years. SPY’s price rose from $43.94 to $771.35 between 29 Jan 1993 and 25 Sep 2026, an average of 8.89% a year before dividends. Rolling three-month cover 5% below at the 25 Sep 2026 price, 4.90% a year, would have cost more than half of that.
It fails on timing. The cover ends on the expiry date. A fall that starts the week after, or that recovers before expiry, pays nothing or less than expected.
It fails when the put is on something different from what you own. A put on SPY covers a portfolio of individual stocks only as far as they move with the S&P 500. A single stock can fall while the index does not.
And the floor is only at expiry. Before then, the put’s price also carries time value, so a sale partway through recovers less than the drop below the strike might suggest. The theta page covers that decay.
Other ways to cap the loss
A smaller position removes risk without a recurring bill; the hedge a position guide starts there. A stop-loss order costs nothing up front but can sell well below its price in a gap, and it cannot buy the shares back. A collar pays for the put by selling a call above the price, which gives up gains beyond that call’s strike.
Related
The put option page covers the contract itself, and hedging the wider idea of paying to remove a risk. Implied volatility explains why the same cover costs more in a falling market. For the order itself, see how to buy a put option, and for getting out before expiry, how to close an option early.
Price a protective put as a yearly bill before buying it. If the yearly cost looks too high for the drop it covers, owning fewer shares is the cheaper way to carry less risk.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.