VIX behavior around monthly SPX OpEx is best studied as an event-window measurement problem. Separate the VIX expiration calendar from the SPX monthly expiration date, then measure pre-event, event-day, and post-event behavior before treating the calendar as a trading signal.
Current SPX anchor
June 18, 2026
The next standard monthly and quarterly SPX-related OpEx is holiday-adjusted to Thursday.
Nearby VIX event
June 17, 2026
Standard VIX expiration is Wednesday, with last trading day June 16, 2026.
Measurement window
T-5 to T+5
Use a fixed window around SPX monthly OpEx, then test whether results are stable across months.
Research rule
Measure, do not assume
Calendar labels are starting points. VIX level, change, volume, OI, and SPX returns decide the evidence.
Direct answer
The useful question is not whether VIX "should" rise or fall around SPX OpEx. The useful question is what VIX did before, during, and after each monthly expiration after controlling for the actual SPX return path, realized volatility, option liquidity, and calendar relationship between standard VIX expiration and the later SPX cycle.
Standard VIX options are not a simple same-day proxy for SPX monthly OpEx. VIX expiration is calculated from the SPX option cycle 30 calendar days later and uses AM settlement. SPX monthly OpEx, SPXW weeklies, and ETF expirations can sit in the same market narrative, but a research workflow should store them as separate events with separate timestamps.
Use this structure before building charts or signals. It keeps the calendar logic explicit and prevents same-day VIX, SPX, SPXW, and ETF events from being mixed together.
| Window | What to measure | Why it matters |
|---|---|---|
| T-5 to T-1 | VIX level and change, SPX return, realized volatility, option volume, open interest, and quote spreads. | This captures pre-OpEx positioning and volatility compression or expansion before the monthly anchor. |
| VIX expiration week | Standard VIX expiration date, last trading day, related SPX monthly cycle, and settlement timing. | VIX expiration can precede the SPX cycle it references, so this belongs in a separate event column. |
| SPX OpEx day | SPX intraday range, close-to-close return, option volume, open interest decay, and chain-level liquidity. | This is the actual monthly expiration event for SPX-related option positioning. |
| T+1 to T+5 | VIX follow-through, SPX reversal or continuation, realized volatility, and renewed weekly expiration flow. | Post-event behavior shows whether the observed move was an expiration effect or broader market regime behavior. |
Use this table to avoid treating VIX expiration and SPX monthly OpEx as the same event. The related SPX date is the standard cycle used in the VIX calendar rule.
| VIX month | VIX expiration | Related SPX monthly cycle | Research note |
|---|---|---|---|
| January | Wednesday, January 21, 2026 | Friday, February 20, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| February | Wednesday, February 18, 2026 | Friday, March 20, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| March | Wednesday, March 18, 2026 | Friday, April 17, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| April | Wednesday, April 15, 2026 | Friday, May 15, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| May | Tuesday, May 19, 2026 | Thursday, June 18, 2026 | Holiday adjustment creates a Tuesday VIX exception; store it explicitly before running event windows. |
| June | Wednesday, June 17, 2026 | Friday, July 17, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| July | Wednesday, July 22, 2026 | Friday, August 21, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| August | Wednesday, August 19, 2026 | Friday, September 18, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| September | Wednesday, September 16, 2026 | Friday, October 16, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| October | Wednesday, October 21, 2026 | Friday, November 20, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| November | Wednesday, November 18, 2026 | Friday, December 18, 2026 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
| December | Wednesday, December 16, 2026 | Friday, January 15, 2027 | Standard VIX date is 30 calendar days before the related SPX monthly cycle. |
Implementation
A defensible implementation starts with two calendars: the standard VIX expiration calendar and the SPX monthly OpEx calendar. After those anchors are explicit, fetch listed SPX expirations, select contracts or chains around the monthly date, and pull quote-aware aggregate evidence over the same event window. Do not merge VIX expiration rows into SPX OpEx rows unless the model has an explicit lag feature.
# 1. Confirm listed SPX expirations before using the calendar anchor
curl "https://api.cutemarkets.com/v1/tickers/expirations/SPX/" \
-H "Authorization: Bearer YOUR_API_KEY"
# 2. Pull contracts for the June 18, 2026 monthly SPX OpEx anchor
curl "https://api.cutemarkets.com/v1/options/contracts/?underlying_ticker=SPX&expiration_date=2026-06-18&limit=100" \
-H "Authorization: Bearer YOUR_API_KEY"
# 3. Measure an event window around a selected SPX contract
curl "https://api.cutemarkets.com/v1/options/aggs/O:SPX260618C06000000/1/day/2026-06-11/2026-06-25/" \
-H "Authorization: Bearer YOUR_API_KEY"VIX options are AM-settled and have a last-trading-day caveat. SPX monthly and SPXW weekly contracts have their own mechanics, so the event table should not collapse them into one date.
Fields: event_type, date, last_trade_date, settlement_type
Compare OpEx windows with non-OpEx control windows. A VIX move that also appears in ordinary weeks is not strong evidence of an expiration-specific effect.
Controls: matched weekday, volatility regime, SPX return bucket
Open interest and volume can change the character of an expiration window, but stale quotes and wide spreads can distort backtests. Add liquidity checks before interpreting VIX-related behavior.
Checks: quote age, spread, volume, open interest
The calendar tells you where to start. The API confirms which expirations and contracts were actually listed before your study pulls quotes, trades, snapshots, or aggregate bars.
Last verified
Date-sensitive calendar references on this page were checked on May 25, 2026. Calendar math is useful for planning, but listed contracts and exchange calendars should still be verified before production workflows run.
No. VIX behavior around SPX OpEx should be measured as an event window. Compare VIX level, VIX change, SPX return, realized volatility, volume, and open interest before treating the date as a signal.
Not usually. Standard VIX expiration is tied to the SPX monthly cycle 30 days later and is AM-settled, while SPX monthly OpEx has its own standard date and settlement mechanics.
A practical first pass is T-5 through T+5 around the SPX monthly expiration, with VIX expiration week handled as a separate calendar event.
Use SPX and VIX dates, SPX returns, VIX level and change, option volume, open interest, quote freshness, and post-expiration follow-through before drawing conclusions.
Related pages
VIX expiration dates
Map every 2026 standard VIX expiration to its related SPX monthly cycle.
Why VIX expires before SPX
Read the 30-day rule and the AM-settlement caveat before running event studies.
June OpEx 2026
Use the June 18 monthly and quarterly OpEx answer as the current SPX anchor.
SPX expiration dates
Separate standard SPX monthly dates from SPXW weekly expiration cycles.
Names of expiring stock options
Start with the dedicated 2026 calendar list of stock and ETF option underlyings.
Expiration data workflow
Use the calendar-vs-listed-expiration workflow before requesting chains, contracts, quotes, or bars.
Full expiration calendar
Use the interactive calendar for weekly, monthly, quarterly, and holiday-adjusted OpEx dates.
Stock options 2026 calendar
Translate expiring-stock lookups into ticker-specific listed option expiration workflows.
Calendar by ticker
Use the ticker-by-ticker 2026 expiration article for SPY, QQQ, AAPL, NVDA, TSLA, IWM, and TLT.
TSLA weekly expirations
Check TSLA weekly expiration dates, 2026 anchors, and the listed-date API workflow.
Next OpEx date
Get the immediate answer for the next standard monthly OpEx and nearby weekly cycles.
Expirations API docs
Fetch listed expiration dates for any underlying ticker with one endpoint.
Options data catalog
Browse contracts, chains, quotes, trades, bars, and reference endpoints.