# 0dteclose

> holding a 0dte at 3:50? enter your strike — see exactly what 4:00 does to it.
> 0DTE expiration simulator (SPX, SPY, QQQ), user-set 3:30/3:45/3:50pm ET close checks, and a dated per-session archive of close vs max pain, walls, implied vs realized — from 15-minute delayed CBOE data. Arithmetic, not advice. CC BY 4.0 for the measured numbers.

## Pages
- [Guides](https://0dteclose.com/guides/): every sourced write-up, one list.
- [Simulator SPX](https://0dteclose.com/simulator/spx/), [SPY](https://0dteclose.com/simulator/spy/), [QQQ](https://0dteclose.com/simulator/qqq/): enter strike/side/price → breakeven, distance, seven close scenarios, settlement mechanics.
- [Daily 0DTE levels SPX](https://0dteclose.com/levels/spx/), [SPY](https://0dteclose.com/levels/spy/), [QQQ](https://0dteclose.com/levels/qqq/): max pain, call/put walls, ATM straddle at 9:00 ET, dated archive per session; Dataset JSON-LD.
- [ATM straddle vs the close SPX](https://0dteclose.com/outcomes/spx/), [SPY](https://0dteclose.com/outcomes/spy/), [QQQ](https://0dteclose.com/outcomes/qqq/): per-session outcome of one 9:45am ET ATM straddle at the official close (mids, ×100, no fills); n disclosed; no statistics until n ≥ 5.
- [Session archive](https://0dteclose.com/sessions/): one dated page per session per underlying; Dataset JSON-LD.
- [Event days Q4 2026](https://0dteclose.com/event-days/): dated FOMC/CPI/OPEX/early-close calendar with primary sources; per-session archive links appear after each day; no event-day statistics until n ≥ 5.
- [Pin rate SPX](https://0dteclose.com/pin-rate/spx/), [SPY](https://0dteclose.com/pin-rate/spy/), [QQQ](https://0dteclose.com/pin-rate/qqq/): measured share of closes within fixed distances of 0DTE max pain, N disclosed.
- [PDT-repeal broker tracker](https://0dteclose.com/pdt/): per-broker post-June-2026 mechanics, dated, flagged when unverified.
- [SPX vs SPY §1256 tax calculator](https://0dteclose.com/tax/spx-vs-spy-1256-calculator/).
- [Methodology](https://0dteclose.com/methodology/): why every pin number is approximate, including ours.
- [How to cite us](https://0dteclose.com/cite/).

## Mechanics
- [What happens if my SPX 0DTE expires in the money?](https://0dteclose.com/expires-in-the-money/spx/): cash-settled to the official S&P 500 close, intrinsic × 100 next business day, no shares; sourced table + broker cutoffs.
- [What happens if my SPY 0DTE expires in the money?](https://0dteclose.com/expires-in-the-money/spy/): OCC exercise-by-exception at $0.01 ITM at the 4:00pm ET close, 100 shares per contract, T+1, trading until 4:15pm ET.
- [What happens if my QQQ 0DTE expires in the money?](https://0dteclose.com/expires-in-the-money/qqq/): same $0.01 rule and clocks as SPY; broker cutoffs compared.
- [Can you get assigned on SPX 0DTE?](https://0dteclose.com/spx-assignment-risk/): European-style, cash-settled — no early assignment; a short ITM contract is debited intrinsic × 100.
- [SPX 0DTE spread at expiration: the cash-settlement math](https://0dteclose.com/spx-spread-cash-settlement/): each SPXW leg cash-settles to intrinsic × 100 on the official close; net capped at width × 100; worked table at five closes; no pin risk.
- [Missed the exercise cutoff on expiration day](https://0dteclose.com/expiration-day-exercise-cutoff/): OCC exercise-by-exception at $0.01 on the 4:00pm ET close; OCC cutoff 5:30pm ET, broker windows earlier (five brokers compared, flagged when unverified); SPX has no cutoff.
- [How much can you lose on a 0DTE option?](https://0dteclose.com/how-much-can-you-lose-0dte/): loss arithmetic by position type at 1/5/10 contracts — long = debit × 100; short call uncapped ((close − strike − credit) × 100); vertical/iron condor = (width − credit) × 100; SPX, SPY, QQQ.
- [How much capital do you need for 0DTE?](https://0dteclose.com/how-much-capital-0dte/): loss arithmetic by position type at 1/5/10 contracts (long = debit × 100; short call uncapped; spread = width − credit) and the 2026 PDT status — no account-size recommendation.

## Key facts
- SPX 0DTE (SPXW) is cash-settled to the official closing index value; SPY/QQQ are physically settled with OCC exercise-by-exception at $0.01 ITM.
- 0DTE contracts expire every trading day; early-close sessions settle at 1:00pm ET.
- Quotes on this site are 15-minute delayed; the as-of time is printed next to every number.

Corrections: corrections@0dteclose.com