One factor that may be partly behind the S&P 500's curious action this week

Traders work during the DPC Holdings Ltd. initial public offering (IPO) on the floor of the New York Stock Exchange (NYSE) in New York, US, on Thursday, June 25, 2026. Michael Nagle | Bloomberg | Getty Images Micron up double-digits after earnings. Positive GDP and inflation data. Apple down big. There were plenty of reasons for stocks to post a big move on Thursday, but the S&P 500 ended almost exactly where it closed Wednesday. Traders faded the overnight rally alongside Micron, sending Nasdaq 100 futures down 3% from their early peak, then bought the dip in the second half. The tech-heavy index ended the session up three-quarters of a percent. That wild ride to nowhere might be a sign that institutional market-makers own options that pay off with volatility, meaning they'll take profits after big moves – buying back puts when the market dips, and selling calls if the market rips. That can keep stocks within a range – a phenomena options traders call "long gamma." Dealers, who are normally selling options, might be more comfortable owning cheaper out-of-the-money bets when they're close to expiring, which will happen on Tuesday's June 30 monthly options expiry. Stock Chart Icon Stock chart icon S&P 500, YTD "Right now dealers are long gamma in both index and in top stocks, so that is stabilizing," said Brent Kochuba, founder of SpotGamma, an options analytics service. …