Expiration And OPEX

What Is Monthly OPEX?

A practical definition of monthly OpEx for traders, developers, and backtesting systems.

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Quick answerLast verified April 28, 2026

Monthly OpEx is the standard monthly options expiration cycle, usually the third Friday of the month. If that Friday is a market holiday, the standard monthly expiration normally moves to the previous business day. It is different from weekly, quarterly, and LEAPS expirations.

Default rule

Third Friday

The standard monthly cycle usually falls on the third Friday.

Holiday rule

Prior business day

June 2026 is a useful example because Juneteenth moves the cycle to Thursday, June 18.

Not the same as

Every Friday

Weekly expirations are separate listed cycles.

Monthly OpEx is a cycle, not a trading signal by itself

The monthly expiration date can concentrate open interest, gamma exposure, and hedging activity, but a date alone is not a complete signal. A data workflow still needs contracts, quotes, trades, open interest, and spread checks.

For research, classify the cycle first. Then measure the data around that cycle instead of assuming all Friday expirations behave the same way.

Expiration cycle comparison

CycleTypical dateUse in data workflows
WeeklyUsually FridayShort-dated scans and event windows.
MonthlyUsually third FridayStandard monthly OpEx analysis.
QuarterlyMarch, June, September, December monthly cyclesOften higher index and ETF open-interest concentration.
LEAPSLong-dated monthly cyclesLong horizon exposure and portfolio overlays.

Last verified

This Q&A page was last reviewed on April 28, 2026. Date-sensitive market calendars, provider docs, and listed contracts can change, so production workflows should verify the live source before trading or publishing an automated answer.

OIC expiration calendarCboe 2026 options calendar

Related questions

Is monthly OpEx always the third Friday?

Usually, but market holidays can move the standard monthly expiration to the previous business day.

Is monthly OpEx the same as weekly expiration?

No. Weekly expirations are listed short-dated cycles and should be classified separately.

Why does monthly OpEx matter for data analysis?

It can concentrate open interest and trading activity, so it is useful to label before measuring quotes, trades, Greeks, and spreads.

Related pages

Options Q&A hub

Browse exact-answer pages for expirations, OCC symbols, options data, and provider comparisons.

Expiration calendar

Use the interactive calendar for weekly, monthly, quarterly, and holiday-adjusted dates.

Expiration API

Fetch listed expiration dates from the API instead of hard-coding calendar rules.

Expirations docs

Review the endpoint used to discover listed option expiration dates.