Most articles on this bury the useful part 2,000 words down. We've gathered the data from studies, exchange reports and real trade databases across the web, and put the answers first.
Here's what the numbers say.
When should you trade — the open or the close?
Short answer: neither.
- The first 15–30 minutes is when the S&P often prints its biggest move of the day. Great if you want direction. Brutal if you're selling premium.
- The last 30 minutes is chaos. Big traders are hedging into the close and price can get shoved around.
- Gamma peaks around 2:00–2:30pm ET — this window often produces the most explosive 15-minute candles of the day.
What real traders actually did. Across 25,000 logged 0DTE trades, the average iron condor was:
- Opened 1 hour 43 minutes after the open
- Closed 2 hours 13 minutes before the close
Not the open. Not the bell. The middle.
How long should you hold?
This is the most useful number in the whole article.
A backtest ran the same trade two ways — one version closed at a 25% profit target, the other held until expiry. Same entries, same strikes, same days. Only the exit changed.
Result:
- Taking the 25% profit won about 9 times in 10
- Holding to expiry won about 3 times in 4
Why? Because when you hold to the close, about 1 in 5 winning trades gave the money back, and nearly as many flipped into a loss.
But here's the part nobody tells you.
Taking profits early caps your upside. On wider positions, holding earned about 2.5× more per trade than taking the 25%.
So:
- Take profits early → win more often, make less per win
- Hold to expiry → win less often, make more per win
That's a trade-off, not a rule. Anyone selling you one as "the answer" is selling something.
Should you buy or sell?
This is the one the data is not conflicted about.
Academic research on retail 0DTE trading found:
- Buyers lose money on average. Retail traders putting on debit trades (paying money upfront) lost $8.05 per contract.
- Sellers were profitable — even after fees.
Read that again if you're buying cheap same-day calls hoping for a 10-bagger. The data says you're on the losing side of that trade.
Selling — morning or afternoon?
Afternoon. And the reason is simple.
- 0DTE time decay is slow in the morning, speeds up through the afternoon, then falls off a cliff — the sharpest drop typically hits around 3:30pm.
- Critically: selling early doesn't get you much more premium than selling later.
So a morning seller takes on hours of extra risk for barely any extra money.
Same premium. Less exposure. That's the whole argument.
At the money or out of the money?
From that same 25,000-trade database — and this one surprises people:
| Structure | Win rate |
|---|---|
| Iron butterfly (at the money) | 72% |
| Iron condor (out of the money) | 63% |
But there's a catch:
- A butterfly can never be a full winner — one side always finishes in the money.
- 94% of iron condors held to expiry were full winners — the whole position expired worthless and the seller kept everything.
Simple version: at-the-money wins more often. Out-of-the-money wins more cleanly.
Quick definitions
If any of that was jargon, here's the plain version. Full glossary on our plain-English terminology page.
- 0DTE — an option expiring today.
- Premium — the price of the option. Buyers pay it, sellers collect it.
- Time decay — options lose value as time passes. On expiry day, fast.
- Iron condor — selling both an out-of-the-money call and put. You win if price stays in a range.
- Iron butterfly — same idea, but sold right at the current price. Bigger premium, tighter range.
- Debit trade — you pay money upfront (buying).
- Credit trade — you collect money upfront (selling).
SPX or SPY?
Both have same-day expiries. They are not the same product.
SPX advantages:
- Cash settled — no shares ever land in your account
- European style — cannot be assigned early
- Section 1256 tax treatment — a 60/40 blended rate instead of 100% short-term
SPY advantages:
- About 1/10th the size, so it works for smaller accounts
Trade-off: SPY carries assignment risk and worse tax treatment.
Now the context — why 0DTE exploded
You didn't imagine the hype. The growth is real:
- 0DTE was 6% of S&P 500 options volume in 2017
- 43% by 2023
- Roughly 50–63% of total SPX options volume on a typical day as of early 2026
And retail is deep in it — more than 75% of retail options trading is now in 0DTE contracts.
The number that should slow you down
Since daily S&P expirations launched in May 2022, retail 0DTE losses have averaged around $350,000 per day — more than $125 million in total.
One study also found 0DTE trades earned 3% lower returns than other option trades, and traders who only traded options lost an average of $547 per month.
This is the same story as most day traders go nowhere. Faster expiries didn't change the maths.
So why do the backtests look so good?
Fair question, and it's the most important thing on this page.
You've just read win rates of 72% and 90%. You've also read that retail loses $350,000 a day. Both are true. Here's how:
- The good numbers come from vendors — companies selling backtesting software and trading platforms. Their data is real, but it comes from a self-selected group of disciplined, often automated traders.
- The loss numbers come from academics looking at everyone.
- A high win rate is not profit. Winning 90% of the time means nothing if the 10% wipes out the 90%.
Also worth knowing: some published 0DTE backtests are quietly tuned. One only traded Mondays, Wednesdays and Fridays because Tuesdays and Thursdays "underperformed" during testing. That's fitting the strategy to the past, not finding an edge.
What to do with all this
Not advice. Just what the data points at:
- The middle of the day beats the open and the close
- Selling has better published outcomes than buying
- Afternoon selling risks less for similar premium
- Taking profits early raises your win rate and lowers your average win
- A win rate is not an edge
And the cheapest move available to you: test it on historical data before you test it with money.