When an SPX option expires in the money, the Options Clearing Corporation cash-settles it automatically. No shares move. The OCC takes the difference between your strike price and the final settlement value of the S&P 500 Index, multiplies by the $100 contract multiplier, and credits or debits your brokerage account. Because SPX contracts are European-style, this only happens at expiration.1Cboe. S&P 500 Index Options Product Specifications
How the Payout Is Calculated
The math is simple. Take the gap between the strike and the settlement value, then multiply by 100. A call struck at 5,000 that settles at 5,050 pays $5,000. A put struck at 5,100 that settles at 5,050 also pays $5,000.1Cboe. S&P 500 Index Options Product Specifications The short side of the trade is debited the same amount. Everything clears through the OCC and the two brokers involved.
This is the practical distinction between SPX and an equity option on an ETF like SPY. With SPY, physical shares actually move at exercise. With SPX, nothing but cash changes hands. That means no commissions on underlying securities and no risk of waking up with an unexpected stock position.
Fees are modest but real. The OCC charges clearing members $0.025 per contract and $1.00 per line item on an exercise notice.2The Options Clearing Corporation. Schedule of Fees Your broker may pass those through directly or bury them in its own exercise and assignment schedule, so check before expiration day.
How the Settlement Price Is Set
The number that decides your payout depends on which SPX product you hold. Monthly and weekly contracts use different methods, and mixing them up is one of the most common mistakes going into expiration.
AM Settlement for Standard Monthly Contracts
Standard monthly SPX options settle on the Special Opening Quotation, or SOQ. On the third Friday of the expiration month, Cboe calculates the SOQ from the actual opening trade price of each S&P 500 constituent on its primary listing exchange. If a stock hasn’t opened yet, its prior close stands in until it does.3Cboe. Settlement of Standard AM Settled SPX Options The final value publishes under the ticker SET.
The SOQ is not the index level you see on your screen at 9:30 a.m. The opening index print blends fresh trades with stale Thursday closes, because not every stock opens at the same instant. The SOQ waits for real opening trades in every name, which makes it internally consistent but potentially quite different from the number your platform is showing.3Cboe. Settlement of Standard AM Settled SPX Options Overnight news, earnings, or pre-market economic data can push the SOQ well away from Thursday’s close, which matters most for short positions counting on the prior day’s tape.
PM Settlement for Weeklies and End-of-Month Contracts
Weekly and end-of-month SPX options trade under the ticker SPXW and use PM settlement. The settlement value is the official closing price of the S&P 500 Index at 4:00 p.m. Eastern on the expiration date.4Cboe Global Markets. S&P 500 Weeklys Options No separate ticker, no waiting for opening prints. What you see at the close is what you get.
PM settlement is more intuitive for most retail traders. You can watch the index in real time and know almost exactly where you stand as the close approaches. The overnight gap risk built into AM settlement is largely absent.
When You Can Still Close the Trade
Standard AM-settled monthly options stop trading at 5:00 p.m. Eastern on the business day before settlement, which is usually the Thursday before the third Friday.1Cboe. S&P 500 Index Options Product Specifications Once Thursday’s session ends, you cannot exit. You ride Friday’s SOQ.
PM-settled SPXW contracts keep trading on expiration day and close at 4:00 p.m. Eastern (3:00 p.m. Chicago). Non-expiring SPXW contracts continue until 4:15 p.m. Eastern.5Cboe Global Markets. SPX Index Options Miss the cutoff and the settlement value locks in without you.
Automatic Exercise
Any SPX option that finishes at least $0.01 in the money is exercised automatically by the OCC and cash-settled. You do not need to call your broker or submit an exercise notice.6Cboe. RG08-073 – OCC Rule Change – Automatic Exercise Thresholds/Expiring Exercise Declarations If you want the cash, do nothing.
There is one narrow exception. Clearing members can submit contrary exercise instructions to block the automatic exercise of an in-the-money option. In practice, a broker could suppress exercise at your request, though this is rare and usually only makes sense when transaction costs or tax consequences would outweigh the intrinsic value.
Options that finish out of the money simply expire worthless. The premium you paid is gone, nothing clears, and the OCC processes nothing.
Tax Treatment
SPX options qualify as Section 1256 contracts, which changes how gains and losses are taxed compared with ordinary stock trades.
The 60/40 Split
Regardless of holding period, 60% of your gain or loss is treated as long-term and 40% as short-term.7Office of the Law Revision Counsel. 26 USC 1256 Section 1256 Contracts Marked to Market A one-day trade and a six-month hold get the same treatment. The top ordinary rate in 2026 is 37%, which applies to the short-term slice.8Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 The long-term slice is taxed at 0%, 15%, or 20% depending on income; for a single filer in 2026 the 20% rate begins above $545,500 in taxable income, and above $613,700 for married couples filing jointly.9Internal Revenue Service. Topic No. 409, Capital Gains and Losses
For a top-bracket trader earning $10,000 on an SPX trade, $6,000 is taxed at 20% and $4,000 at 37%, a blended rate near 26.8%. The same $10,000 earned on a stock held two weeks would be taxed entirely at 37%. Section 1256 activity gets reported on IRS Form 6781.10Internal Revenue Service. About Form 6781, Gains and Losses From Section 1256 Contracts and Straddles
Year-End Mark-to-Market
If you hold an open SPX position on the last business day of the tax year, the IRS treats it as if you sold it at fair market value that day. Unrealized gain or loss is recognized and taxed for that year.7Office of the Law Revision Counsel. 26 USC 1256 Section 1256 Contracts Marked to Market When you close the position later, your basis resets to that year-end value and you report only the additional change. The 60/40 split applies to the mark-to-market amount as well.
Loss Carryback and the Wash Sale Exemption
A net Section 1256 loss for the year can be carried back three years and applied against Section 1256 gains in those earlier years, potentially producing a refund. The carryback goes to the earliest year first and cannot create or increase a net operating loss in the carryback year.11Internal Revenue Service. Form 6781, Gains and Losses From Section 1256 Contracts and Straddles
The wash sale rule under 26 U.S.C. ยง 1091 does not apply to losses recognized through the Section 1256 mark-to-market provision.7Office of the Law Revision Counsel. 26 USC 1256 Section 1256 Contracts Marked to Market You can close an SPX position at a loss and reopen a similar one the next day without forfeiting the deduction on the year-end mark-to-market portion.
Net Investment Income Tax
High earners face an additional 3.8% Net Investment Income Tax on the lesser of net investment income or the amount by which modified AGI exceeds $200,000 for single filers ($250,000 for married filing jointly). SPX gains count.12Internal Revenue Service. Net Investment Income Tax For a top-bracket trader, the true ceiling on the short-term slice is 40.8% and on the long-term slice 23.8%. Worth factoring into any estimate of what an in-the-money settlement actually delivers after tax.