The U.S. stock market is experiencing a rare, synchronized selling storm as both institutional and retail investors retreat, leading to a sharp deterioration in market sentiment.
On March 20, data from Goldman Sachs' trading desk revealed that long-only funds executed a net sale of equities totaling $9.6 billion in a single day. This marks the highest figure recorded by the bank since it began tracking this data in 2022 and has been characterized as a "5-sigma event."
Concurrently, data from J.P. Morgan shows that retail investor inflows fell 15% week-over-week. Since the outbreak of the Iran conflict, cumulative inflows have plummeted by 43%, indicating a severe crisis of confidence in the "buy-the-dip" strategy.
This selling frenzy is set against a backdrop of persistent Middle East instability. High oil prices, a lack of clear market direction, and a reassessment of massive capital expenditures in AI are collectively suppressing investor risk appetite. Goldman Sachs warns that as the quarter-end approaches and dealer gamma exposure worsens post-options expiration, any market downturn could be amplified by negative gamma effects, suggesting there is still room for further panic to be absorbed.
**Historic Selling: Long-Only Funds Set Net Selling Record** Data from Goldman Sachs' trading desk confirmed the $9.6 billion net sale by long-only funds on March 20, surpassing the previous record of $8.8 billion set on July 31, 2025, to become the largest single-day net sale in the bank's dataset.
The selling was broad-based across all sectors, with the most significant selling pressure observed in Technology, Media, and Telecom (TMT), Consumer Discretionary, and Industrial sectors. Goldman Sachs trader Mike Washington noted that overall trading activity rated a 7 out of 10, a clear increase from the subdued levels of preceding days, with the final transaction volume skewing 15% toward selling compared to the 30-day average.
In contrast to long-only funds, hedge funds were modest net buyers of $750 million on the same day. Buying interest was primarily driven by scattered covering demand in macro products, alternative assets, and the healthcare sector.
**Market Structure: Unwinding Hedges Triggers "Capital Cleansing"** This large-scale selling is not an isolated event but rather a concentrated release of previously built-up structural pressures. Nomura's Charlie McElligott had previously pointed out that institutional investors' selling of S&P 500 futures was near record levels, and ETF short positions were also at historically high levels, indicating that Wall Street was effectively over-hedged against a major risk-off scenario.
However, this over-hedging created a "most distorted scenario": the market moved sideways instead of crashing, rendering downside hedges ineffective and forcing investors to continuously bear the cost of these hedges. As high volatility mechanically compressed positions, hedge positions were gradually unwound. The resulting delta covering, paradoxically, provided underlying support for the market, creating a "the-more-it-falls-the-more-someone-buys" dynamic.
This week, the VIX and S&P 500 futures diverged—volatility fell significantly while equities accelerated their de-risking. This culminated in a concentrated "capital cleansing" on the morning of March 20. Stocks fell nearly 1% intraday but staged a strong rebound in the afternoon following comments from the Israeli Prime Minister, ultimately closing with minor losses.
**Retail Retreat: 43% Drop Reflects Fading Wealth Effect** The institutional turmoil has spread to the retail market. According to J.P. Morgan's weekly retail flow report, retail inflows fell to $5.7 billion for the week ending March 18, below the 12-month average of $7.0 billion per week. ETF purchases dropped approximately 22% week-over-week, while single-stock purchases remained around the 45th percentile of their historical range over the past year. Since the Iran conflict began, total retail investment has cumulatively declined by 43%.
J.P. Morgan attributes this trend to two reinforcing factors: first, high oil prices and the market's daily, directionless volatility are suppressing risk appetite; second, the profitability of retail portfolios is deteriorating—although year-to-date returns remain positive, some early gains have been erased since the conflict began, significantly weakening the wealth effect.
Referencing historical patterns from the post-2020 inflation period, J.P. Morgan noted that rising gasoline prices and CPI eroded the growth of retail trading portfolios and led to a significant slowdown in trading activity, which only resumed gradually after inflation stabilized from its peak.
Despite the overall cautious sentiment, the thematic allocation logic for individual stocks among retail investors has not fundamentally changed. AI data center and electrification-related stocks remain primary buying targets. Notably, the relative trading volume of energy call options has seen a clear uptick, with retail investors positioning in oil-sensitive outperformers ahead of institutions, contrasting with their behavior during the Russia-Ukraine conflict. J.P. Morgan points out that during major oil supply shocks, the historical correlation between the S&P 500 and oil prices tends to weaken and eventually turn negative, reflecting the impact of margin pressures and tightening financial conditions.
**Negative Gamma Risk vs. Ceasefire Hopes** Goldman Sachs maintains a cautious outlook. The bank's derivatives traders note that dealers are currently in a net short gamma position, and any downward market movement would deepen this short exposure. Goldman estimates that a 1.5% market decline could expand dealer gamma exposure to approximately $5 billion net short. The impact of quarter-end rebalancing is expected to exceed the effects of this week's quadruple witching expiration.
On the geopolitical front, Goldman Sachs, referencing market patterns during the Russia-Ukraine conflict, cautions investors that news of ceasefire talks often serves as the first major catalyst. However, history suggests that the day after such announcements typically presents an opportunity to sell into strength rather than a signal to chase rallies. Rich Privorotsky, head of Goldman's Delta One desk, indicated that whether Iran allows the U.S. a political off-ramp or continues to exert soft pressure via the Strait of Hormuz will be a key variable determining market direction.
Given that the market still has room to absorb more panic, Goldman Sachs currently favors holding short delta structures and put spreads on the S&P 500 or Nasdaq 100.
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