Shares of GameStop Corp. (GME) rocketed nearly 130% since Thursday’s close after short seller Citron Research said on Friday that it will stop commenting on the video game retailer’s stock following the actions of angry retail traders on Reddit.

The move came after Citron postponed a planned livestream, during which the investor said it would detail the reasons it believes GameStop’s stock price will drop to $20, due to  “multiple hack attempts'' on its Twitter account and “harassment of minor children.”

“What Citron has experienced in the past 48 hours is nothing short of shameful and a sad commentary on the state of the investment community,”  Citron’s managing director, Andrew Left, said in a Friday letter that has since been removed from Twitter. “We are investors who put safety and family first and when we believe this has been compromised, it is our duty to walk away from a stock.”

“We will no longer be commenting on GameStop, not because we don’t believe in our investment thesis, but rather the angry mob who owns this stock has spent the past 48 hours committing multiple crimes,” Left continued, noting that he will be bringing evidence to the FBI and Securities and Exchange Commission (SEC). 

GameStop and Citron both did not immediately respond to requests for comment.

A Battle Between Bulls and Bears

Citron later released the video, not as a livestream, and said it believes GameStop is overvalued because it is falling behind competitors as the gaming environment shifts from physical games to online downloads. Moreover, the short seller said the “failing mall-based retailer” relies on an “antiquated” business model of having customers trade in old games and consoles, something Citron said consumers are no longer interested in doing. 

Citron said the “expensive” stock trades at 40-times EBITDA, adding the analysts have a consensus $12 mark on the stock.

However, Citron is in a battle with a new class of retail investors and day traders that have flooded the stock market since COVID-19 hit the U.S. last March. Many of them have been part of a buying boom in the markets last year and chased after stocks like Hertz that became penny stocks as their business collapsed due to the pandemic. Online forums like Reddit's WallStreetBets have become a hangout for new and experienced day traders, and a ripe environment for pump and dump stock schemes.

As shares of GameStop soared on retail investor-fueled euphoria, short sellers who were faced with mounting losses and high borrowing fees were also forced to close their positions and buy, prompting what is known as a short squeeze.

Shares of GameStop popped 51% on Friday, closing at a record $65.01, and then jumped an additional 48.5% to $96.55 on Monday at 12 p.m. By 12:30 pm, shares had collapsed and turned negative for the session, but have been bouncing wildly throughout the day.

GameStop’s wild ride on Monday comes after it more than doubled during the week of Jan. 11 and marks the most volatile 10-day trading period on record, according to Bloomberg data. The New York Stock Exchange halted trading in the stock at least four times over this period.

GameStop was the most actively traded U.S. company with a market cap above $200 million at one point, as millions of shares were traded every few minutes, according to Bloomberg data. More than 193 million shares exchanged hands on Friday, making it the most active day for the retailer since its IPO in 2002.

Gamestop shares

Top shareholders in GameStop include Fidelity Investments, RC Ventures, and BlackRock. In June 2020, the company added two directors to its board after shareholders voted in favor of a slate of nominees advanced by activist investors Hestia Capital Partners and Permit Capital Enterprise Fund during a proxy contest. The company announced further board refreshment on Jan. 11 after striking a deal with Chewy co-founder Ryan Cohen, agreeing to add him and two others to its board after Cohen urged the company to better focus on digital sales.

GameStop reported a net loss of $18.8 million for the third quarter of 2020 ended Oct. 31, compared to a net loss of $83.4 million during the same period in 2019. While this was an improvement, net sales for the retailer declined to $1 billion, compared to $1.4 billion the year prior. Total sales for the holiday season ended Jan. 2 declined 3.1% year-over-year.