The GameStop Short Squeeze and the Clearing Call of January 2021

Before dawn on Thursday 28 January 2021, an automated notice from the National Securities Clearing Corporation landed in the risk systems of Robinhood Securities. It was a margin call, of the kind that clearing members receive and settle without anyone outside the building noticing. This one asked for roughly three billion dollars, against a firm that had held about seven hundred million dollars of excess net capital a few weeks earlier. Within hours Robinhood had switched off the buy button on thirteen stocks, a hundred thousand people were filing into a class action, and a Texas video-game retailer with declining revenue and 5,509 stores had become the most argued-about security on earth.

GameStop Corp. closed 2020 at $18.84 a share on the New York Stock Exchange. On 27 January 2021 it closed at $347.51, valuing a company that had lost money in each of the two preceding fiscal years at roughly $24 billion. Nothing in the business had changed. What changed was that a crowded short position met a crowd, and the settlement machinery underneath both of them turned out to have a hard capacity limit nobody had priced.

A Crowded Short in a Shrinking Float

GameStop sold physical discs from strip-mall storefronts while its customers were downloading games directly to consoles. Revenue fell from $9.2 billion in fiscal 2017 to $6.5 billion in fiscal 2019, and the company closed stores by the hundred. For a professional short seller the thesis wrote itself: a melting-ice-cube retailer with operating leases, a secular demand shift, and no obvious buyer.

So many funds reached the same conclusion that the position stopped behaving like a short. By the end of December 2020, reported short interest stood at about 71 million shares against roughly 70 million shares outstanding — more than 100 per cent of the company. Measured against free float, which strips out insider and strategic holdings, the commonly cited figures ran above 140 per cent in mid-January.

That arithmetic is only possible because of how stock lending works. A short seller borrows a share, sells it, and the buyer receives a share that can itself be lent again. Gene D'Avolio's study of the institutional loan market documented how thin and how fragile the supply side of that market is: borrow is cheap and abundant until suddenly it is neither, and recall risk sits with the borrower (D'Avolio, 2002). Owen Lamont and Richard Thaler had shown, using the tech-stock carve-outs of 1999 and 2000, that where borrow is scarce enough a security can trade at a price arbitrage cannot touch for months at a time (Lamont and Thaler, 2003). Andrei Shleifer and Robert Vishny had already made the general point that arbitrage is performed by agents running other people's money, who face redemptions and margin calls exactly when their positions move against them — so the trade that is most obviously right on paper is the one most likely to be liquidated before it pays (Shleifer and Vishny, 1997).

Ryan Cohen supplied the catalyst. The founder of the pet-supplies retailer Chewy had built a stake through RC Ventures, disclosed at 9 per cent in a filing in August 2020 and later raised to about 12.9 per cent. On 11 January 2021 GameStop announced that Cohen and two former Chewy executives, Alan Attal and Jim Grube, were joining its board. The stock, which had spent the autumn in the teens, began to move.

Options, Dealers, and the Reflexive Bid

Fuel came from the options market. Retail brokerages had made short-dated out-of-the-money calls almost frictionless to buy, and buyers of those calls were on the other side of dealers who hedge by purchasing the underlying stock. As GameStop rose, dealers had to buy more shares to stay delta-neutral, which pushed the stock higher, which forced more buying — the mechanism traders call a gamma squeeze. Layered on top of it, short sellers covering their borrow had to buy the same scarce shares.

Brad Barber, Xing Huang, Terrance Odean and Christopher Schwarz, studying Robinhood's own aggregate user holdings, found that the platform's traders concentrated into a small number of attention-grabbing names in herds far tighter than those of other retail brokerages (Barber et al., 2022). Markus Brunnermeier and Lasse Heje Pedersen had modelled the predatory case years earlier: when a large trader is known to be forced to unwind, other participants trade in the same direction first, deepening the move they profit from (Brunnermeier and Pedersen, 2005). In January 2021 the distressed large trader was the short seller, the predators were dispersed and anonymous, and short-interest data published by vendors such as S3 Partners told everyone where the bodies were buried.

Information of that kind was pooled on r/wallstreetbets, a Reddit board that entered January with something under two million subscribers and finished the month with several times that. Its most-followed poster was Keith Gill, a Massachusetts-based chartered financial analyst who had bought about $53,000 of GameStop calls and shares in mid-2019 and had been posting screenshots of the position ever since under the name Roaring Kitty. His case was a conventional deep-value argument: net cash, a solvent balance sheet, a console refresh cycle, and a short position he thought was too big for the float.

Nine Sessions

Nine trading days carried almost the whole move. On 13 January the shares rose 57 per cent to $31.40 on no company news. On 22 January they closed at $65.01. Over the weekend that followed, the position of Melvin Capital — Gabe Plotkin's fund, a Steve Cohen protégé who had launched in 2014 and compounded well for six years — became public knowledge, and the squeeze acquired a named target.

Citadel and its partners put $2 billion into Melvin on 25 January and Point72 added $750 million, a rescue of a fund that had entered the year with about $12.5 billion under management. Melvin closed the GameStop short the next day and finished January down 53 per cent. Vendor estimates put mark-to-market losses across all GameStop short sellers at close to $20 billion for the month.

Then came 28 January. GameStop traded as high as $483 in the pre-market. Shortly after the open, Robinhood, Interactive Brokers, Trading 212 and several other retail platforms restricted opening purchases in GameStop, AMC Entertainment, BlackBerry, Koss and a handful of other heavily shorted names. Customers could sell; they could not buy. The stock fell 44 per cent to close at $193.60.

The Plumbing Call

The explanation was not a conspiracy against small investors, though that was the immediate and widely held assumption. It was collateral.

American equities settled two business days after trade date in January 2021. During those two days the NSCC stands between buyer and seller and carries the risk that one of them fails, and it covers that risk by holding a clearing fund deposit from each member, sized by the volatility and concentration of that member's unsettled book. Robinhood's unsettled book was concentrated in precisely the securities whose volatility had gone vertical. The deposit requirement scaled accordingly, and a surcharge known as the excess capital premium — triggered when a member's requirement runs far beyond its net capital — added roughly $2.2 billion on its own.

Vlad Tenev, Robinhood's chief executive, told the House Committee on Financial Services on 18 February that the firm had been notified of a deposit deficit of approximately $3 billion. After it restricted opening purchases, reducing its forward risk, the NSCC waived the excess capital premium and the requirement fell to about $1.4 billion. Robinhood raised $1 billion from its existing investors overnight and a further $2.4 billion the following week. "Despite the unprecedented market conditions in January," Tenev testified, "at the end of the day, what happened is unacceptable to us."

Keith Gill testified at the same hearing, and opened by addressing the speculation about who he actually was. "A few things I am not," he wrote in his prepared statement. "I am not a cat. I am not an institutional investor, nor am I a hedge fund. I do not have clients and I do not provide personalised investment advice for fees or commissions."

A venue changing the terms of trade in the middle of a squeeze had a close precedent. When the Commodity Exchange imposed liquidation-only rules during the Hunt brothers' silver corner in 1980, the same accusation followed: that the rule-makers had positions on one side. The older precedent for the settlement problem itself is the Wall Street paperwork crisis of 1967 to 1970, which closed more than a hundred brokerages and produced the central depository that the 2021 system is built on.

What the Investigations Found

The Securities and Exchange Commission published its staff report on equity and options market structure conditions in early 2021 on 18 October that year. Its central finding disappointed both camps. The run-up did coincide with short covering, the staff wrote, but the covering did not last long enough to explain the shape of the move: "it was positive sentiment, not the buying-to-cover, that sustained the weeks-long price appreciation of GameStop stock." By the reckoning of the report, this was less a classical squeeze than a very large number of people buying the same thing at once while a short position happened to be trapped inside it.

Its authors raised four structural questions rather than assigning blame: whether forced sales of shares to cover shorts amplify moves, whether payment for order flow and the routing of retail orders to wholesalers creates conflicts, whether gamification of trading applications encourages volume that is not in the customer's interest, and whether the two-day settlement cycle imposes clearing costs that transmit stress into customer access.

Regulatory consequences followed the fourth question most directly. FINRA fined Robinhood $70 million in June 2021 for outages and approval of options trading for unsuitable customers, the largest penalty it had imposed. The Commission voted in February 2023 to shorten the settlement cycle, and T+1 took effect on 28 May 2024 — halving the window during which clearing members carry unsettled risk, and with it the size of the deposit call that had shut the buy button.

What Was Left

Melvin Capital never recovered its footing; Plotkin told investors in May 2022 that he was winding the fund down. Short sellers as a class moved away from crowded, heavily reported positions in small-capitalisation names. GameStop itself did the sensible thing a company does when its shares detach from its business: it sold them. Equity offerings in April and June 2021 raised $551 million and $1.126 billion, wiping out the debt and giving the balance sheet years of runway that no operating plan had produced. Cohen became chairman in June 2021.

Two months after the squeeze, the same prime brokers who had been on the wrong side of GameStop's borrow discovered a different concentration problem in the collapse of Bill Hwang's family office, where the leverage was hidden in swaps rather than published in short-interest tables. Both events turned on the same blind spot: participants could see their own exposure clearly and the aggregate exposure not at all.

The durable lesson of January 2021 is narrower than the culture war it produced. A market can absorb a great deal of disagreement about what a company is worth. What it cannot absorb is a clearing system sized for ordinary volatility meeting a book concentrated in the least ordinary securities on the tape. The buy button went dark not because someone decided small investors should lose, but because a risk model built in the 1970s asked a brokerage for three billion dollars it did not have on a Thursday morning, and the brokerage had exactly one lever to pull.