S&P 500's 13% rally driven by short covering, Nasdaq 100 next

The S&P 500 jumped 1.5% and 1.8% in back-to-back sessions to fresh record highs, a surge Bloomberg macro strategist Simon White attributes to forced short covering that could extend to the Nasdaq 100.

"The Nasdaq's short-covering intensity yesterday was milder than the S&P 500's, meaning a larger unwinding may still be ahead," White said.

Goldman Sachs' "most shorted" basket climbed 13% over four trading days, confirming the squeeze. Short interest in the Invesco QQQ Trust remains elevated, while ratios for S&P 500 and Russell 2000 ETFs have declined. Software stocks, hit by thematic shorting tied to coding agents, show a recent jump in median short interest.

If the squeeze reaches the Nasdaq 100, index momentum could accelerate. But White warns inflation and real-rate risks persist, leaving the rally vulnerable to a bull trap.

Short-Covering Signal Flashes on S&P 500

White's framework flags a squeeze when a single-day gain exceeds 1.5 standard deviations of the prior month's average daily move, futures open interest declines, and the index hits an eight-week high — all triggered on the S&P 500. Data back to 1998 show the signal's one-month average return beats the overall mean, though three-, six-, and twelve-month returns run slightly below, suggesting the pop is short-lived rather than the start of a trend.

The record close Tuesday was the S&P 500's first in two months, with the index up about 13% in 2026. The Philadelphia semiconductor index remains down about 17% from its late-June peak even after a rebound, while the forward price-to-earnings ratio on the S&P 500 has moderated to 20.4 from 22.2 at the end of 2025.

Nasdaq 100 Holds the Key

The Nasdaq 100 has yet to break its record high, and its unfinished short-covering space may be larger. QQQ short interest in the latest data, from 10 to 14 days ago, remains high even as S&P 500 and Russell 2000 ETF ratios fell. Software is a case in point: median short interest jumped as coding-agent fears drove thematic shorting, with positions built recently and stop levels not yet touched by current prices.

Underweight investors returning to the market could add a second driver as the S&P 500 clears prior highs. But the rally's durability hinges on the macro backdrop — the 10-year Treasury yield at 4.63% and oil below $80 a barrel have eased inflation worries, yet any reversal risks a sharp pullback that would punish late short-covering chasers.

This article is for informational purposes only and does not constitute investment advice.