Tactical · same-day and next-day puts · · built ( New York), before the US open

A big down day in negative gamma: which 0DTE put, and what does it pay?

The thesis: every index book is in negative gamma, semiconductors are in a washout and the narrative has turned ("AI wash-out"), so Thursday extends Wednesday's fall, and a same-day put on QQQ or SMH captures it with defined risk. This page gives the hedging levels for today's and Friday's expiries, the size of move the options price, what has actually happened the day after sessions like yesterday, and the candidate puts priced for a range of opens. Quotes are Wednesday's close (after-hours levels for the ETFs); re-check live prices at the open, 15:30 CET.

The setup in one paragraph. Overnight the thesis has support: Nasdaq futures are down about 0.9% and QQQ traded to $722 after hours (−0.9% from the $728.95 close), SMH to $555 (−1.7%). Dealer positioning is one-way: across all expiries QQQ is −$7.9 billion of gamma per 1% move and SMH −$0.8 billion, and in today's and Friday's expiries alone QQQ carries −$3.8 billion with the put wall at $725, SMH −$0.4 billion with the wall at $560; both walls are already above the after-hours price, so the hedging flow at the open is selling, and the next shelves are QQQ $705–700 (100,000 puts open in Friday's expiry) and SMH $550, $540 and $535. Against the thesis: TSMC reported a beat this morning (net profit NT$763 billion, +69%, above the NT$743 billion consensus; gross margin 66.4%), the VIX closed at 16.9, and the record of the last year is mean-reversion: the day after a −3% SMH session was up 60% of the time (mean +0.9%), the day after a −2% QQQ session up 78%; SMH closed lower than −2% the next day in 13% of those cases, QQQ never. The options agree: QQQ's same-day straddle prices ±1.1% and gives a −2% close a 7% chance; SMH's prices ±2.3% and gives −3% a 15% chance. A same-day put is therefore a bet against the base rate at roughly the market's odds, with negative gamma as the reason it can pay many times over if it is right. The way to hold that bet: slightly out of the money, not deep (the deep strikes pay only on a −4% day, which has a 1-in-1,000 implied chance on QQQ), sized as a full loss, bought after the first 15 minutes if the open does not bounce, and cut if QQQ reclaims $725 or SMH $560, the walls that would mean the dealers have turned.

Recommendation

QQQ, same-day (15 Oct) $718 put: about $2.15 ($215) at a −0.5% open near $718.5, break-even −0.9% from the after-hours level ($715.85). Pays about 1.5× if QQQ closes −1% ($714.9), 4.8× at −2%, 8× at −3%; worthless at or above $718. It sits just under the $725 wall and above the $705–700 shelf, so a break of the wall runs straight into its money. The $720 put ($3.19, break-even −0.7%) is the safer strike (3.9× at −2%, 1.6× at −1%); the $715 put ($1.07) the sharper one (6.9× at −2%, but nothing at −1%). Do not go below $715: the $710 and lower strikes need a −2% close just to break even and the market gives that 7%.
SMH: use Friday's expiry, not today's. Today's SMH expiry has 7,000 contracts open and $0.50–1.50 wide quotes on $1–3 options, so the spread eats a third of the premium. Friday's (16 Oct, the monthly) has 633,000 open: the 16 Oct $545 put at about $3.90 ($390) at a −0.5% open (17,000 open at $550, 8,000 at $545; spread 1.56/2.41 at the close). Marked at today's close it is worth about 1.3× at −1%, 2.1× at −2%, 3× at −3%, 5× at −5%, and 0.8× if flat, because a day remains; it also keeps the position for Friday's expiry, the largest gamma event of the quarter. The $550 put ($5.79, tightest spread) is the conservative choice (1.9× at −2%).
SPY same-day $766 put ($1.67 at a −0.5% open) is the cheapest index expression: 2.5× at −1%, 7× at −2%. But SPY is the resilient book (−1% on the week against −10% for SMH) and sits on its own $765 wall; it is a worse fit for the semiconductor narrative.
Execution. Wait for the first 15 minutes: a gap down that is bought back through $725 (QQQ) or $560 (SMH) in the first half hour is the mean-reversion pattern of this year and ends the trade; a gap down that holds below the walls is the entry. Use limit orders at the mid; 0DTE quotes move every second. Take half off at 2× and let the rest run into the last hour, where negative-gamma days do their damage; exit everything if QQQ trades back above $725 or SMH above $560 at any time.
Size as a full loss. The historical odds are against this trade and the payoff is a multiple only if the day is a −2% day or worse. Risk what you are prepared to lose entirely: one or two contracts, about 0.3–0.5% of the account, not a position.

Method

Chains: CBOE delayed quotes at Wednesday's close (the ETF "spot" shown is CBOE's last after-hours print; the regular close is used for the gamma and levels). Dealer gamma: open interest across all expiries, and separately for today's and Friday's expiries only, recomputed with Black-Scholes at the close; sign convention as elsewhere on this site (dealers long customers' sold calls, short customers' bought puts). Expected move: the at-the-money straddle in each expiry at the close, converted to a daily standard deviation (straddle ≈ 0.8σ) and a normal probability of each close. Base rates: next-day returns in the last 252 sessions after days with the stated condition (prior day ≤ −2% for QQQ and SPY, ≤ −3% for SMH; five-day return ≤ −3% / −8%). Candidate prices: Black-Scholes with each option's own implied volatility (+3 points on a lower open), 6.5 hours to the close for same-day options; scenario values are intrinsic at the close for same-day expiries and the model value with one day left (volatility +5 points on a −1% or worse day) for Friday's. "Expected value, thesis" is the per-contract expectation under a normal distribution centred on −2% (QQQ, SPY) or −3% (SMH) with the market's daily standard deviation; at the market's own distribution a fairly priced option has an expected value of about zero minus the spread. Bars: Interactive Brokers (dashboard refresh of this morning). Prices on this page are indicative; the live quote at the open is what you pay.