OpEx Explained: Monthly Options Expiration in Equities and Crypto

OpEx - options expiration - is the moment when large blocks of gamma disappear from dealer books and get replaced with the next cycle. It sits at the intersection of calendar mechanics and dealer flow. Trading OpEx well requires understanding both. This guide covers the equity side (third-Friday monthly, quad witching) and the crypto side (Friday 08:00 UTC on Deribit) together.

The equity OpEx calendar

Third-Friday monthly OpEx

Every calendar month, the third Friday is the standard equity OpEx. Monthly SPX, SPY, single-stock, and index options expire together. This concentrates the largest open interest of any weekly cycle and produces the heaviest dealer hedging window of the month.

Quadruple witching

Four times a year - in March, June, September, and December - the third Friday is also the expiration of stock-index futures, stock-index options, stock options, and single-stock futures at the same time. This is quadruple witching. Volume in the final hour of these sessions is typically 2–3x a normal Friday close.

Weekly and daily OpEx

In modern SPX, weekly options list Monday through Friday and daily options list Monday through Friday for the zero-day trade. The third-Friday monthly still carries the largest per-expiry OI, but the volume distribution across the week is much flatter than it was five years ago. Every day now has meaningful expiration flow.

AM vs PM settlement

Monthly SPX options are AM-settled - they settle on the special opening quote (SOQ) at the Friday open, not at the close. Weekly and daily SPX are PM-settled. This distinction matters: AM-settled options stop trading Thursday, and the Friday open on OpEx week can gap unusually because the AM-settled cycle prints its SOQ without further liquidity.

The crypto OpEx parallel

Deribit is the primary crypto options venue. Weekly, monthly, and quarterly BTC and ETH options all expire Friday at 08:00 UTC. The mechanics are direct analogues of equity OpEx.

Friday 08:00 UTC weekly

Every Friday morning, the standard weekly settles alongside the Friday daily. The Asian and early European sessions in the lead-up produce the highest concentration of intraday 0DTE flow of the crypto week.

Quarterly OpEx

The last Friday of March, June, September, and December is the crypto quarterly OpEx. Historically, the largest open-interest concentrations of the year print into these expiries. Both retail and institutional books use them as calendar anchors for structured trades.

The 24/7 twist

Unlike equities, crypto trades continuously through OpEx. Positioning can shift right up to the settlement window, and the post-08:00 UTC hours often produce sharper moves than any equity session would show. The pattern is the same - expiry releases pent-up direction - but the execution happens without a pause.

OpEx is not an event that predicts direction. It is a recurring dealer-flow regime change. Everything that traded orderly under the expiring gamma may trade very differently under the new one - and the transition is where most of the alpha (and the pain) lives.

The gamma roll

The single most important concept for trading OpEx is understanding what happens to dealer gamma across the transition.

Before expiry

Dealer books hold gamma from every non-expired contract. The expiring cycle concentrates the near-term gamma - for a Friday close, most of the actionable intraday gamma is in the Friday daily and weekly. As spot moves, dealers hedge that gamma actively.

At expiry

Every expiring contract settles to intrinsic value. The gamma associated with those contracts drops to zero instantly. What was the largest source of intraday hedging flow disappears in a single print.

After expiry

Dealers now hold the next-cycle gamma without the expiring cycle’s counterweight. The new positioning may be similar in sign to the old, or it may be opposite. If similar, price behaviour continues roughly as before. If opposite, the character of the tape flips - pinning becomes trending, or vice versa.

The roll trade

Sophisticated traders read the new positioning as it builds. On flow-measured GEX, the new-cycle sign is visible within minutes of expiry. On OI-based GEX, it takes until the next daily update. The traders who read the roll fastest are trading with the regime; the ones reading the old cycle are trading a stale playbook.

Common OpEx playbooks

• The pin trade. In confirmed positive-gamma OpEx weeks, sell strangles centered on max pain and let dealer hedging pull spot into the strike. Close before the expiry window rather than trying to catch every last dollar of pin.
• The unpin trade. Buy directional exposure into the Monday after equity OpEx. The gamma release often lets pent-up direction resolve in the days after expiry, especially post-quad witching.
• The stand-aside trade. During quad witching or the final 30 minutes of crypto quarterly OpEx, noise dominates signal. Sizing down or stepping aside is a legitimate strategy for discretionary traders without a specific edge.
• The roll read. Watch the flow-derived dealer positioning on the new cycle as expiry clears. If the new sign is opposite the old, the character change is imminent. Trade the retest of the first meaningful level under the new regime.
• The single-name playbook. Post-OpEx weeks in equities show elevated dispersion - index pins release and single names revert to their own stories. Long options on names with pinned idiosyncratic risk into OpEx often work in the days after.

What OpEx does not do

It does not tell you what direction the release will go. It does not guarantee a pin. It does not eliminate the need for a thesis. Traders who lean on OpEx as a standalone signal - “buy the OpEx dip, sell the post-OpEx” - tend to eventually get run over on the sessions where the pattern breaks. OpEx is a structural regime marker, not a strategy in itself.

Common OpEx misconceptions

“OpEx is always bullish.” Historically OpEx weeks show a mild positive skew in equities but with wide dispersion. It is not a reliable directional signal on its own.

“Post-OpEx always moves.” The tendency is for higher realised vol post-expiry than pre-, but there are plenty of quiet weeks after OpEx. The gamma release enables movement - it does not require it.

“Weekly options killed OpEx.” The rise of dailies and weeklies has spread out the OpEx effect but has not eliminated it. Third-Friday monthly still carries the largest open-interest concentrations, and quad witching still produces the most volatile last-hour closes of the year.

“Crypto doesn’t have OpEx.” Crypto has an even cleaner OpEx: single Friday 08:00 UTC settlement on Deribit, with clearly-defined weekly, monthly, and quarterly cycles. The mechanics are the same as equities.

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