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Expiry selection & 0DTE

You never read “the” GEX—you read one expiration, or a cumulative slice that ends on a chosen expiration. Start by checking the calendar date, DTE, and key role flag, then account for how same-day (0DTE) gamma behaves differently from multi-week positioning.

0 0DTE / Front session

Nearest listed expiration

Same-day (0DTE) when today has a listed expiry; otherwise the closest upcoming session. Check the printed date and DTE.

1 Next session out

Second listed expiration

The next available expiration date after 0. On daily index chains this is often tomorrow; on single stocks it may be next week.

W1W2W3W4 Multi-day / Weekly

Key weekly roles

The next four standard weekly expirations. Ideal for comparing near-term term structure and catalyst weeks.

M1M2M3 30–90+ DTE OpEx

Monthly OpEx roles

The next three standard monthly (third-Friday) expirations where institutional open interest typically concentrates.

ALL Full chain horizon

Furthest available expiration — full chain in Cumulative mode

In Cumulative mode, aggregates every eligible expiration after today through the final listed date. In Standalone, isolates only that furthest date.

Roles are assigned dynamically from the symbol’s listed chain. One date can carry more than one role badge (for example, 0 and W1 on a Friday).

Flag	Meaning	Typical read
`0`	Nearest available expiry	Same-day (`0DTE`) only when the displayed date is today; otherwise read its actual DTE.
`1`	Second available expiry	The next listed date after the nearest; not necessarily tomorrow.
`W1`–`W4`	Weeklies	A few days to a couple of weeks out.
`M1`–`M3`	Monthlies (third Friday)	Swing structure, large OpEx positioning, and calendars.
`ALL`	Furthest available expiry	Whole available chain in Cumulative mode (with the today-exclusion rule).

Flags are assigned from the symbol’s listed chain. The nearest expiry and a weekly or monthly role can refer to the same date, and dates without a key flag remain accessible when Key Only is turned off. Check earnings dates alongside the strip, and note that GEX History/Replay tracks these key roles across historical sessions.

How 0DTE behaves close to expiration

As expiration approaches, gamma compresses sharply toward the at-the-money (ATM) strike. For comparable near-the-money options, shorter time to expiration means much steeper gamma curvature—while far-OTM same-day options carry very little gamma unless spot moves toward them.

Do not rank expirations by DTE alone: a massive monthly OpEx concentration can outweigh a thin near-dated chain. Compare net exposure and open-interest share across expirations in GEX Matrix.
Charm (delta decay over time): on a same-day option, delta changes rapidly as the clock ticks even if spot price barely moves, which can require ongoing hedge adjustments during the session.
Today’s aggregation rule: on today’s 0 bubble, both Standalone and Cumulative represent today’s book alone. Selecting any later expiration in Cumulative mode excludes today so fast-decaying 0DTE gamma does not distort your multi-day swing map. See Standalone and cumulative.
Minute refresh vs. scheduled snapshots: because 0DTE positioning evolves intraday with volume flow, the WebApp refreshes about once a minute (and Copy Levels lets you paste a fresh snapshot into TradingView between scheduled indicator updates).

High 0DTE volume is not the same as high net dealer risk

Large gross trading volume at a strike can be balanced by two-sided customer flow. In its historical SPX study, Cboe distinguishes gross 0DTE volume from market makers’ net gamma exposure—which is why comparing OI and volume columns alongside Net GEX is essential. For Chris Pulver’s morning SPX walkthrough, see Daily prep and education.

Where you see it

TanukiTrade documentation. Levels are context, not a recommendation. tanukitrade.com