Use 0DTE and overnight Gamma sections

Expiration scope and trading session are separate

Gamma → 0DTE focuses the selected chain on contracts expiring on its trading date. Gamma → Overnight focuses on eligible overnight observations. They are independent choices: a short-dated expiration does not imply a regular-hours-only dataset, and an overnight session does not mean every listed option in the family trades then. The exact roots, date and calendar remain part of the analysis.

Choose the date before interpreting 0DTE

An overnight trading date can begin on the previous calendar evening, so your computer's date is not enough.

1. Set the underlying family and selected trading date.
2. Open 0DTE and verify the expiration scope in the tool chips.
3. Choose RTH, GTH or Combined according to the available instrument/session.
4. Read the current valuation minute and input freshness.
5. Open the Overnight section for eligible overnight comparisons.
6. Match selections before comparing with a broader all-expiry view.

Cash closure changes reference availability

Options can continue trading while a cash index is closed. Eligible off-cash views may use an explicitly implied reference rather than an official current index print. That estimate needs matching dated observations and must keep its methodology label. A last regular-session model and a current overnight model are not the same snapshot. Never interpret an empty overnight interval as permission to carry an old value forward without a label.

Worked interpretation: midnight changes the wall clock

Suppose you inspect an overnight session after midnight and expect a different 0DTE expiration because the calendar day changed. Check the exchange trading date and exact listed expirations first. Keep that selection fixed and compare GTH with Combined. Combined can include additional eligible segments, while a complete GTH result alone says nothing about a missing RTH prefix. A difference between them is not automatically a calculation bug or an entitlement failure.

Troubleshoot unavailable overnight exposure

Check whether the exact root supports overnight trading and whether your account has the required access. Then inspect market closure/intermission, stale underlying references and pending model history. Regular-only roots do not acquire valid GTH input because another root in the family supports it. Include exact date, root, session and implied-reference label when opening a ticket. Avoid presenting a current futures quote as proof that the options chain is also complete.

Model, perspective and units

Exposure is a sensitivity calculation, not an execution total. GEX means gamma exposure, DEX means delta exposure, VEX means vanna exposure, and CEX means charm exposure; charm can also be called CHEX. VEX does not mean vega in these tools. Select the metric before comparing colors or magnitudes. Per 1% move, per $1 move and per unit are distinct choices. Read the returned unit rather than assuming that every displayed dollar amount means money paid for contracts.

Classic OI applies a positioning proxy to dated open interest. Flow-adjusted modeling incorporates eligible classified intraday volume into that proxy. Neither reveals actual dealer inventory or every hedge. Dealer and customer perspectives can reverse signs while retaining the underlying sensitivity calculation. A positive bar is therefore meaningful only with its metric, model, perspective, expiration selection and valuation time. Record those settings together when sharing a view, and match them before expecting two tools to return comparable values.

Preserve the calendar and reference in comparisons

Near expiry, small changes in eligible valuation inputs can materially alter modeled sensitivities. A 0DTE screenshot should therefore include the precise selected minute, expiry and session instead of only the underlying symbol. Compare it with an all-expiry view at the same cutoff before describing one concentration as the market's total exposure. Adding farther expirations can offset the nearest date, and a family can include roots whose listings and overnight behavior differ.

For overnight reference prices, distinguish an official cash close, a labeled implied current estimate and an actual traded futures price. They occupy related but different evidence roles. A missing same-contract anchor or stale futures input can make an estimate unavailable even when yesterday's official close remains visible. The overnight display window itself does not guarantee continuous observations through maintenance, weekends or closures. When reporting a seemingly wrong 0DTE date, include the exchange trading date and local wall-clock time so support can reproduce the boundary rather than assuming midnight alone selects the next session.