What is 0DTE?

0DTE is the most talked-about corner of the options market and one of the least explained.

Let me fix that.

0DTE stands for zero days to expiration. A 0DTE option is an option on the last day of its life. It expires at today's close.

That's it. It isn't a special product. It isn't a new kind of contract. Every option ever listed becomes a 0DTE option eventually, the same way every carton of milk eventually reaches its sell-by date.

If puts and calls are still fuzzy, start with What is a put option? What is a call option? The short version: a put is insurance and a call is a hedged bet.

0DTE is both of those with a few hours left on the clock.

How expiration day became every day

For most of options history, expiration day came once a month. The third Friday. Then the exchanges added weekly expirations.

Then in 2022, Cboe filled in the last gaps for S&P 500 index options. Since May 16, 2022, an SPX option has expired every single trading day.

That changed everything. 0DTE stopped being something that happened to your position once a month. It became something you could trade every morning.

Traders noticed. In July 2026, Cboe reported that 0DTE contracts made up a record 66.2% of all SPX options volume. That's two out of every three contracts.

Today you'll find 0DTE in three places:

1. Index options such as SPX, XSP and RUT, with an expiration every trading day.
2. ETF options such as SPY, QQQ and IWM, also every trading day.
3. Single stocks such as TSLA and NVDA, on their weekly expiration day.

Why traders love it

It's easy to understand the appeal. There are four honest reasons 0DTE took over.

1. The stake is small. An option with hours left has very little time value, so the premium is cheap.
2. The buyer's worst case is known. The most you can lose is what you paid. That's the hedged bet at work.
3. Nothing carries overnight. You're done by the close. No headline at 2:00 AM can gap your position.
4. You get an answer today. No waiting three weeks to find out if you were right.

Sellers have their own reason. Premium that takes weeks to decay on a monthly option decays in one afternoon. If you read the put and call post, you'll recognize the insurance company collecting on a policy that lasts until 4:00 PM.

Those are real advantages. They're also the reasons people overtrade it.

What's different on the last day

The contract is the same. The behavior is not.

Time decay runs on fast-forward. A monthly option loses its time value over weeks. A 0DTE option loses all of it between the opening bell and the close. Every quiet hour costs the buyer money and pays the seller.

Small moves cause big swings. A few points in the index can double a 0DTE option or cut it in half. Traders call this gamma. You don't need the Greek letter to feel it.

There is no tomorrow. With a 30-day option, being early is survivable. With 0DTE, being right at 4:05 PM is the same as being wrong.

How it ends depends on what you traded. This one catches new traders off guard, so here are the two most popular products side by side.

An SPX option that finishes in the money pays cash and disappears. A SPY option that finishes in the money can leave you owning or owing 100 shares after the close.

What the record actually shows

Definitions only get you so far. Here's a real one from the StrikeZone IQ board.

On October 6, 2026 at 10:00 AM, SPX was near 7826. The 7850 call cost about $3.50. Across 1,101 past sessions, a call at that same distance from spot, bought at that same minute:

• Returned 2x at some point during the day 40.4% of the time.
• Was still worth 2x at the close 14.1% of the time.
• Expired worthless 78.5% of the time.

Read those again. Four days in ten, the double showed up. On most of those days it was gone by the close.

That's 0DTE in three numbers. The opportunity is real. It's brief. And the default outcome is zero.

Sellers see the mirror image. A put sold 51 points below spot that same morning went in the money at some point during the day 9.8% of the time. It finished there 4.6% of the time.

Going in the money is not staying there.

These are historical odds, not predictions. They tell you what happened before. They don't tell you what happens today.

Same puts, same calls, one day

So what is 0DTE? It's the options you already know, traded on the day they expire. The contract doesn't change. The clock does.

In the put and call post I gave you one question to ask before every trade. Am I buying insurance, selling insurance, making a bet, or taking the other side of one?

For 0DTE, add a second question:

How often has this worked, from this distance, at this time of day?

That second question is why I built StrikeZone IQ. It shows the historical odds behind every 0DTE strike, for buyers and for sellers, counted across real past sessions.

Next up: the expected move, the ruler every 0DTE trade should be measured against.