After a quick rebound that almost wiped out a sharp mid‑week slide, U.S. stocks are facing fresh selling pressure this week from trend‑following algorithmic funds, according to a major financial institution’s trading desk.
The S&P 500 has already slipped below a short‑term trigger that has set off selling by commodity trading advisers (CTAs). Those systematic strategies, which trade on market direction rather than fundamentals, are expected to remain net sellers for the rest of the week, no matter how the market moves.
A renewed decline could unleash about $33 billion of selling this week. If the index falls below 6,707, the data show that up to $80 billion of additional systematic selling could be triggered over the next month. In a flat market, CTAs are projected to unload roughly $15.4 billion of U.S. equities this week, and even if stocks rally, they could still shed around $8.7 billion.
Investor stress was high last week. The firm’s Panic Index—a composite of implied volatility, VIX, put‑call skew and the slope of the volatility term structure—stood at 9.22, a level that signals markets are close to “max fear.”
After a sharp drop early in the week, the S&P 500 surged 2% on Friday, marking its biggest gain since May. That rally followed an early‑week slide triggered by a new AI automation tool from Anthropic PBC, which shook software, financial services and asset‑management stocks as investors reassessed disruption risks.
On top of CTA selling, thin liquidity and a shift to short‑gamma positioning are keeping the market choppy, potentially amplifying swings in either direction as dealers adjust their positions. Top‑of‑book liquidity—the volume of buy and sell orders at the best bid and lowest ask—has fallen sharply, dropping to about $4.1 million from a year‑to‑date average of roughly $13.7 million.
“The inability to transfer risk quickly lends itself to a choppier intraday tape and delays stabilization in overall price action,” the desk wrote in a note to clients.
Option dealer positioning has also flipped. After occupying a long‑gamma zone that helped keep the index below 7,000, dealers are now estimated to be flat to short gamma. The dynamic becomes more pronounced when liquidity is scarce, so traders warned to “buckle up.”
Other systematic cohorts still have room to de‑risk. Risk‑parity positioning sits in the 81st percentile over the past year, while volatility‑control strategies are in the 71st percentile. Unlike CTAs, these funds respond to sustained changes in realized volatility, so their impact would grow if volatility remains high. Realized volatility in the S&P 500 is on the rise, but the 20‑day gauge is still below the levels seen in November and December.
Seasonality offers little relief. February has historically been a weaker and choppier month for both the S&P 500 and the Nasdaq 100, as supportive January flows—such as retirement contributions and peak retail activity—fade.
Retail behavior shows signs of fatigue. After a year of relentless dip‑buying, the latest two‑day net retail imbalance revealed roughly $690 million of selling last week, indicating less willingness to “buy all dips.” Popular retail trades tied to crypto and crypto‑linked equities have been hit especially hard, raising the risk that a broader rotation out of U.S. stocks would mark a notable shift from last year’s trading patterns.
