GameStop 2021: The Full Story — Short Interest, WallStreetBets, the Gamma Squeeze, and the Trading Halts

This article tells that story as documented narrative — the setup, the surge, the restrictions, and the retracement — drawing throughout on the SEC's October 2021 staff report and the congressional record. The mechanism vocabulary (squeezes, gamma, settlement margin) was built in Pillar 11's short-squeeze article and the meme-stock category piece; this is the history those pieces point at. Per the pillar's standing rules: the documented record only, no villains beyond it, and the retracement — where the late buyers lived — stays in the story.

The setup (2019 – January 2021): a value thesis meets a crowded short

The documented ingredients assembled slowly. The company: GameStop, a physical retailer in a digitising industry — declining revenues, store closures, a consensus bear case so widely held that short interest reached levels among the highest ever recorded for a US equity, reported at times around or above 100% of the public float (a legal artefact of shares being lent, sold, and re-lent, as the SEC report explains — not proof of naked shorting, a distinction the report addresses directly). The other side: a documented value thesis predating the mania — investors including Michael Burry took positions in 2019–20 arguing the balance sheet and console cycle were underpriced; in 2020, e-commerce entrepreneur Ryan Cohen accumulated a large stake, pressed publicly for digital transformation, and on January 11, 2021 joined the board with two allies — the news event that lit the fuse. The crowd: on Reddit's WallStreetBets, the stock had a long-running champion — Keith Gill, posting as DeepF***ingValue — whose 2019–20 posts documented a fundamental case in public months before any squeeze talk; by late 2020 the forum's attention had concentrated, and the extreme short interest itself became the story: the crowd could see, in published data, a mechanically vulnerable position. The kindling was exactly the anatomy the mechanism article teaches: scarce float, record short interest, a catalyst, and — new in kind — a coordination layer of millions reading the same posts.

Two weeks in January: the surge, documented

The sequence, per the SEC report and market data. Week one: after the Cohen board news, the stock broke out of its teens — closing around $31 on January 13, roughly doubling in days, with options volume exploding alongside. The acceleration (January 22–27): the 22nd saw the first violent session (intraday spikes above $70 on enormous volume); Monday the 25th opened with wild swings and repeated volatility halts; the 26th closed near $148 as mainstream and social-media attention went global; the 27th closed at $347.51 — up roughly 1,700% year-to-date — as documented short positions absorbed historic losses: Melvin Capital, the most publicly identified short, lost 53% in January and received a $2.75 billion capital infusion from Citadel and Point72 (documented in congressional testimony); other funds closed shorts at large documented losses. The SEC's central analytical finding belongs here, because it corrects the folklore: examining the actual flows, the staff concluded that the rise was driven predominantly by direct buying pressure — sustained, mostly small-lot purchases — with short covering a small fraction of volume, and gamma hedging (dealers buying shares against the torrent of call options) a contributing but not dominant channel. The squeeze was real; the crowd's buying was the larger force — the measured record's version of the story, reported here over the mythologised one. The peak: January 28 opened in chaos, printing an intraday high of $483 before what happened next redirected the story.

January 28: the restrictions, and the plumbing behind them

On the morning of January 28, Robinhood and several other brokerages restricted their customers to position-closing only in GameStop and a set of related stocks — retail could sell but not buy — and the price collapsed intraday to $112 before closing at $193.60. The move produced immediate public fury and a durable conspiracy narrative: that brokers had rescued institutional shorts by switching off the buy side. The documented explanation runs through the plumbing this portal built in Pillar 6: equities then settled in two days (T+2), and between trade and settlement the clearinghouse (NSCC) collects risk-based margin from brokers; extreme volatility in concentrated names sent Robinhood's morning deposit requirement to roughly $3.7 billion — far beyond its liquidity — and after the buying restrictions and a waived excess-capital premium the requirement fell to about $1.4 billion, met with drawn credit lines and an emergency $3.4 billion capital raise over the following days (figures per congressional testimony and the SEC report). The SEC report found the restrictions were a response to clearing-margin demands, while noting — as did the February 18, 2021 House hearing — the deeper questions it raised about brokerage capitalisation, payment for order flow, and gamified trading, which the aftermath article takes up. Reported per the no-villains rule: the documented sequence supports a liquidity-and-margin explanation and documents no buy-side conspiracy; it also documents that the restriction fell entirely on the retail side of the market at the exact peak — both facts stand, and the policy argument they opened is reported in the next article as the live debate it remains. The retracement: restrictions eased within days, but the peak never returned — the stock fell below $50 by mid-February, an ~90% drawdown from the intraday high, before a second, smaller documented run in late February–March; buyers near the January peak absorbed severe documented losses, per the treatment this pillar owes every episode. The February–May 2021 hearings produced the era's public record — including Gill's testimony ("I like the stock") — and the SEC's October 2021 report closed the investigative arc with the analytical findings threaded through this article, explicitly identifying no illegal coordination in the crowd's buying while flagging the structural questions the next article catalogues.