Two things happened in U.S. markets in the first half of 2026 that nobody seems to be talking about together. First, same-day-expiry S&P 500 options kept taking over the index options market. Second, on June 4, 2026, the pattern day trader rule, the $25,000 speed bump that limited how often small margin accounts could day trade, went away. Put those side by side and you get the most interesting retail-trading question of the year: what happens when the fastest-decaying product in the market meets the loosest day-trading rules in 25 years?
What happened
0DTE keeps growing
Cboe, which lists SPX options, has been tracking the rise of zero-days-to-expiration (0DTE) contracts for years. Its own data points tell the story:
- In May 2025, 0DTE options made up more than 61% of SPX volume, a record at the time and up 9 percentage points from April. Cboe said the jump was powered by retail traders, who accounted for about 54% of SPX 0DTE volume (Cboe).
- In August 2025, the share hit a new record of about 62.4%, with retail estimated at around 53% of 0DTE volume (Cboe).
- In Q2 2026, Cboe's investor slides showed 0DTE options surging to 65% of SPX volume alongside record revenue, according to Investing.com.
The PDT rule disappears
Meanwhile, FINRA's elimination of the pattern day trader designation and $25,000 minimum took effect on June 4, 2026 (FINRA Regulatory Notice 26-10), replaced by an intraday margin standard that focuses on margin deficits rather than trade counts. Brokers may phase it in until October 20, 2027.
Why futures traders should care
If you trade ES or MES, 0DTE isn't someone else's hobby. It's part of your order flow. The core concern critics raise is that market makers hedging large 0DTE positions could move the underlying index intraday, amplifying or dampening moves depending on how dealers are positioned. That hedging happens in the same S&P complex you trade.
Cboe's own research disagrees with the scariest version of that story. Its analysis, "Evaluating the Market Impact of SPX 0DTE Options," and a related research paper, "0DTE Index Options and Market Volatility: How Large is Their Impact?", conclude that 0DTE activity does not destabilize the market. Other commentators have blamed 0DTE for everything from increasing intraday volatility to suppressing it.
The controversy: both sides
The defenders: 0DTE options give traders precise, short-term exposure with defined premium at risk. Cboe's research finds limited market-wide impact. Some academic work on retail option trading, such as Bogousslavsky and Muravyev's "An Anatomy of Retail Option Trading", has examined retail behavior in detail rather than assuming it is uniformly reckless. And the end of the PDT rule removes an arbitrary wealth test that critics said kept small traders out.
The critics: a contract that expires the same day is extremely sensitive to small moves in the underlying and can go to zero within hours. Relative bid-ask spreads on cheap, short-dated options can be wide, which quietly taxes frequent traders. Removing the trade-count limit means a small account can now cycle through those contracts as often as its margin allows. More freedom plus a faster product is a recipe for faster outcomes, good and bad.
Our take
Our take: We don't think 0DTE is a market-crash machine, and we don't think the PDT rule was protecting anyone well. But we'd be lying if we said the timing looks great. The PDT rule, for all its flaws, forced small accounts to pick their spots. That friction is gone at the same moment same-day options have become the dominant way retail plays the S&P. Also worth saying out loud: Cboe's research is valuable, but Cboe is also the exchange earning record revenue from this product. Read it the way you'd read any company's research on its own bestseller.
The uncomfortable question: if the $25K rule was protecting small traders from anything, the first evidence will show up in 0DTE P&L. Will anyone, brokers, exchanges or FINRA, publish that data?
What traders should do (general, not advice)
- If you trade 0DTE, track your costs (spreads and commissions) separately from your directional P&L. That's where frequent traders often leak.
- Just because you can now make more day trades doesn't mean you should. Set your own daily trade limit.
- If you trade ES/MES, pay attention to intraday behavior around heavy 0DTE activity and form your own evidence-based view rather than relying on social-media narratives.
Key takeaways
- Cboe data showed 0DTE at about 61% of SPX volume in May 2025 and 62.4% in August 2025; Q2 2026 slides reported 65%.
- Retail traders accounted for over half of SPX 0DTE volume in Cboe's 2025 estimates.
- The PDT rule's $25,000 minimum ended June 4, 2026, removing the day-trade count for small margin accounts (with phase-in to Oct. 2027).
- Cboe's research finds little destabilizing impact from 0DTE; critics remain worried about dealer hedging and retail costs.
- Our view: the combination deserves data, not slogans. Set your own limits now that the rule doesn't.
Put the research to work on your Desk
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FAQ
What share of SPX volume is 0DTE?
Cboe reported about 61% in May 2025 and a record 62.4% in August 2025; Investing.com reported Cboe's Q2 2026 slides showed 0DTE at 65% of SPX volume.
Do 0DTE options destabilize the market?
Cboe's research concludes they do not. Critics worry dealer hedging of large 0DTE positions could amplify intraday moves. The debate is ongoing.
Does the end of the PDT rule affect options traders?
Yes. Stock and options margin accounts are no longer subject to the day-trade count or $25,000 minimum once their broker implements FINRA's new intraday margin standard (effective June 4, 2026, with phase-in to October 20, 2027).
Loomi.Ai provides educational market research, not financial advice. Trading futures and options involves substantial risk of loss, and backtested results are historical and do not guarantee future returns.
Sources
- SPX 0DTE Options Jump to 61% Share on Retail Resurgence, Cboe
- SPX 0DTE Options Jump to Record 62% Share in August, Cboe
- Cboe Q2 2026 slides: record revenue, 0DTE options surge to 65% of SPX, Investing.com
- Evaluating the Market Impact of SPX 0DTE Options, Cboe
- 0DTE Index Options and Market Volatility: How Large is Their Impact?, Cboe (research publication)
- Regulatory Notice 26-10, FINRA
- An Anatomy of Retail Option Trading (Bogousslavsky & Muravyev), LSU Finance Mardi Gras conference paper