Triple Witching Explained: Quarterly Expiration Dates, What Happens, and What to Do with Your Positions

On Friday, September 18, 2026, US stock options, S&P 500 index options and E-mini S&P 500 futures all expired together, and the quarterly S&P index rebalance took effect after the close. The S&P 500 finished the day up just 0.17%. That is the typical triple witching: an enormous amount of trading that mostly cancels out. The next one is Friday, December 18, 2026. If you are new to how expiration works at all, read options expiration (OPEX) explained first; this article covers the quarterly version.

What is triple witching?

Triple witching is the quarterly day when three kinds of derivatives expire at once: stock options, stock index options and stock index futures. It falls on the third Friday of March, June, September and December, and it usually produces some of the heaviest trading volume of the quarter.

Ordinary monthly expiration, on the third Friday of every month, already concentrates a lot of option open interest. On the quarterly dates, the quarterly index futures contracts — such as E-mini S&P 500 futures — expire as well, along with the large quarterly option series that institutions use for hedging. Funds that want to keep their exposure have to roll it into the next quarter, which adds volume in the days before.

The name is market slang, not an official term. Exchanges simply call it quarterly expiration. The “witching hour” originally referred to the final hour of trading, when the expiring contracts and their hedges were unwound and prices could swing.

What is quad witching, and is it different?

Quad witching is the same day with a fourth contract, single-stock futures, added to the list. Single-stock futures traded in the US from 2002 on OneChicago, and for those years four kinds of contracts expired on the quarterly Friday.

OneChicago closed in 2020, so the fourth contract no longer trades in the US, and “triple witching” is once again the accurate term. Many traders and news outlets still say “quad witching” out of habit. They mean the same day. If you see either term, the date to plan around is the third Friday of the quarter-end month.

When is triple witching in 2026 and 2027?

Triple witching falls on the third Friday of March, June, September and December. When the stock exchange is closed that Friday, expiration moves to the business day before, usually Thursday. That happened in June 2026 and will happen again in June 2027, both because of Juneteenth.

What actually happens on triple witching day?

Three things happen at once on triple witching day: expiring contracts settle, index funds rebalance, and dealers unwind the hedges tied to the expiring options. Each pushes volume into two windows, the open and the closing auction.

• The open: special opening quotation. Standard monthly SPX options and quarterly E-mini S&P 500 futures settle on a special opening quotation (SOQ) of the index, calculated from the opening prices of every stock in it on Friday morning. Traders holding positions into that settlement need the opening prints, which concentrates orders at 9:30 a.m.
• The close: rebalances and PM-settled options. S&P Dow Jones Indices’ quarterly rebalances, covering share counts, float adjustments and index changes, take effect before the open on the Monday after the third Friday. Index funds that track them trade at Friday’s closing price, so the closing auction can be one of the largest of the year. SPXW, SPY and single-stock options settle on that close too.
• In between: hedges come off. Dealers who sold options hedge with stock or futures. As those options expire, the hedges are no longer needed and are unwound. If dealers were long a lot of gamma near one strike, that unwinding can hold the index near the strike into the close, then release it.

The rebalance is often the bigger flow of the two. When a stock joins or leaves the S&P 500, or its weight changes sharply, index funds have to trade it at the close regardless of price, and that order imbalance is published before the auction.

Does triple witching move stock prices?

On average, no more than an ordinary day. On the 11 quarterly expirations from March 2024 to September 2026 the S&P 500 moved an average of 0.59% close to close, against 0.65% for all trading days over the same period. The median, 0.49%, was almost identical to the all-day median of 0.50%. The index rose six times and fell five.

That matches what the mechanics predict. Much of the expiration volume is offsetting: rolls, hedges coming off and index trades that are matched against each other in the auction. The volume is real; the directional pressure mostly isn’t. The two largest moves in the sample, March 20, 2026 (−1.51%) and June 18, 2026 (+1.08%), coincided with macro news in a volatile spring rather than anything specific to expiration.

Where expiration does show up is in the character of the following week. When dealers were long gamma into the expiration and that gamma rolls off, the market often feels looser for a few sessions; when they were short gamma, expiration can remove an accelerant. Our guide to gamma exposure (GEX) shows how to read which side dealers are on.

How do different contracts settle on triple witching?

The key is which of your contracts settle on Friday’s open and which on Friday’s close. Getting that wrong is the most common, and most avoidable, triple-witching mistake.

Standard SPX options are the trap. Under Cboe’s rules they stop trading at the close on Thursday and settle on Friday’s opening quotation. If you hold a short monthly SPX put through Thursday’s close, you carry the overnight gap with no way to adjust. Weekly SPXW options with the same Friday date trade until 4:00 p.m. Friday and settle on the close, as do SPY and single-stock options. For a fuller comparison of morning and afternoon settlement, see the OPEX guide.

For single stocks and ETFs, the risk is assignment. Options that finish at least one cent in the money are normally exercised automatically. A short call that finishes a few cents in the money can turn 100 shares per contract into a sale, with tax consequences if the shares are low-basis, and you won’t know for sure until the weekend.

What should you do with your positions before triple witching?

Decide on every expiring position by Thursday, and don’t leave near-the-money short options to the last hour on Friday.

An illustrative example. You own 3,000 shares of a large tech stock bought years ago at $40, now trading at $198, and you sold 30 December $200 covered calls for income. With a week to go, the stock is at $199.

1. Do nothing. If the stock closes at $200.05 Friday, the calls are assigned and you sell 3,000 shares at $200, realizing about $480,000 of long-term gain you hadn’t planned for. If it closes at $199.95, you keep the shares. Pin risk makes this close to a coin toss.
2. Roll on Thursday. Buy back the December $200 calls and sell March 2027 calls at a higher strike, for a net credit or a small debit. You keep the shares and push the decision out a quarter. Our guide to rolling options to avoid assignment covers the mechanics.
3. Close for a small loss. Buy back the calls and keep the shares, writing new calls after the rebalance week when the market has settled.

For short puts, the logic is the same in reverse: if you don’t want to buy the shares, roll or close before the final hour. For long options with value, selling is usually cheaper than exercising, because exercise means paying for, or delivering, the full share amount.

How does triple witching fit with the macro calendar?

Triple witching often shares a week with a Fed decision or a CPI release, and the combination matters more than either alone. The FOMC usually meets in mid-March, mid-June, mid-September and mid-December, so a Wednesday decision followed by a Friday expiration is common. The heavy event premium before the Fed sits on the same options that expire two days later.

Check the week as a whole. The December 18, 2026 expiration follows the December 10 CPI release, and the jobs report on December 4. Our guides to FOMC week, CPI day and the weekly market outlook show how to layer the events. If you write calls or puts for income, the week after triple witching is often the cleaner moment to reset positions: the event premium has gone, the rebalance is done, and the new quarter’s open interest has not yet built up.

What is a triple-witching checklist?

1. A month ahead, confirm the date on the Cboe or OCC calendar, especially if a holiday is near the third Friday.
2. The Monday of expiration week, list every option position expiring that Friday, and whether it settles on the open or the close.
3. Check the macro calendar: FOMC, CPI and any large earnings in the same week.
4. Note the largest open-interest strikes on the index and your main holdings; expect pinning pressure near them.
5. By Thursday afternoon, roll, close or accept assignment on every near-the-money short option. Close monthly SPX positions before Thursday’s close if you can’t carry the overnight gap.
6. Avoid large market orders at the open and in the closing auction on Friday; use limit orders mid-session.
7. The following week, re-check dealer gamma and implied volatility before writing new options.

Frequently asked questions

Key takeaways

1. Triple witching is the quarterly expiration of stock options, index options and index futures on the third Friday of March, June, September and December.
2. Remaining dates: December 18, 2026; March 19, June 17 (Thursday), September 17 and December 17, 2027.
3. S&P index rebalances take effect after the same Friday close, so the closing auction is often among the busiest of the year.
4. It is a volume event, not a direction event: the S&P 500 averaged a 0.59% move on witching days from 2024 to 2026, against 0.65% on all days.
5. Know which contracts settle on the Friday open (SPX monthlies, index futures) and which on the close (SPXW, SPY, single stocks).
6. Roll or close near-the-money short options before the final hour, and expect the market to feel looser once expiring hedges roll off.

Sources and method

1. NYSE, Holidays and trading hours — Juneteenth observed Friday, June 18, 2027; 2026 and 2027 holiday calendar
2. Cboe, SPX options specifications — SPX last trading day before settlement and SPXW 4:00 p.m. expiration
3. CME Group, E-mini S&P 500 contract specifications — quarterly futures expiry and settlement
4. CME Group, Navigating the S&P 500 rebalance — quarterly rebalance on the third Friday of March, June, September and December
5. FRED, S&P 500 (SP500) — daily closes used for expiration-day moves

Expiration dates are the third Friday of each quarter-end month, moved to the preceding business day when the NYSE is closed (June 18, 2026 and June 17, 2027 for Juneteenth). Expiration-day moves are close-to-close S&P 500 changes (FRED SP500) on the 11 quarterly expirations from March 15, 2024 to September 18, 2026, compared with all trading days from January 2024 to October 14, 2026. The settlement matrix is a summary of exchange rules plus a qualitative Proflex risk assessment. Worked examples are illustrative.