Wall StreetB次元官网网址檚 mania over GameStop is on again, at least for one afternoon.

Shares in the troubled video game company more than doubled Wednesday to $91.71 apiece, the stockB次元官网网址檚 best day since Jan. 27, when it was going for $347.51 a share.

A rally in GameStop has been rare since it fell back to earth early this month. The stock, which soared 1,600% at one point in January, has been extremely volatile.. ItB次元官网网址檚 down nearly 72% so far in February, though itB次元官网网址檚 still up nearly 387% this year.

Shares in AMC Entertainment, another stock hyped by online social media forums, jumped 18.1%. The movie theatre chainB次元官网网址檚 stock is up nearly 60% this month and about 329% this year.

The sudden, sharp move higher in GameStop and AMC Entertainment left even some members of RedditB次元官网网址檚 WallStreetBets forum, which helped cheer the stocksB次元官网网址� meteoric rise last month, scratching their heads.

B次元官网网址淐an we honestly sound off on what we think is happening?B次元官网网址� wrote one Redditor. B次元官网网址淚s there any reason for this 150% spike??B次元官网网址� asked another.

GameStopB次元官网网址檚 wild ride shocked Wall Street, forcing the market to gird for more volatility. It prompted Congress to hold a House hearing last week into what led to the frenzy and whether smaller investors need to be shielded from taking big risks.

Individual investors on Reddit and other social media forums encouraged each other to buy GameStop, AMC Entertainment and select other stocks in a bid to hurt hedge funds that were betting the stocks would lose value. The move, known as a B次元官网网址渟hort squeeze,B次元官网网址� can lead traders who were using options to bet against a stock to abandon their bets. To do so, they have to buy shares of the stock, which pushes the price even higher.

GameStop was an extreme example because some of its shares had been sold short multiple times.

Gust Kepler, CEO of stocks and options platform BlackBoxStocks, said that he became aware around 3:30 EST Wednesday of B次元官网网址渁ggressive buyingB次元官网网址� of call options on GameStop shares. A call option gives a trader the right to buy a stock at a certain price at a later date.

B次元官网网址淚 am not certain that thereB次元官网网址檚 another short squeeze going on like the one before, however, there are probably some funds who stayed short assuming the dust would settle,B次元官网网址� Kepler said.

Another possible reason for GameStopB次元官网网址檚 sharp move: The Grapevine, Texas, company announced Wednesday that its chief financial officer will be resigning on March 26.

B次元官网网址淭he CFO exited the company and thereB次元官网网址檚 talk of the company finally transforming from a brick and mortar to deploying their product in a digital way, and this is why we believe the stock shot up at the end of the day today,B次元官网网址� Kepler said.

Some of the traders who bid up GameStopB次元官网网址檚 shares last month cited optimism that new board member Ryan Cohen, the founder of online pet store Chewy, would help turn the struggling retailerB次元官网网址檚 fortunes around.

The company has been struggling to adapt to the rise of mobile gaming and digital downloads that have rendered its more than 5,000 stores obsolete, even more so during the pandemic.

Some market watchers speculated that GameStopB次元官网网址檚 surprise reanimation was a reaction to critical comments from Charlie Munger, Warren BuffettB次元官网网址檚 right-hand man.

Speaking at the annual meeting of Los Angeles Daily Journal Wednesday, the Berkshire Hathaway vice chairman pinned the GameStop stock frenzy on small investors that he said were gambling on the stock market.

B次元官网网址淭hatB次元官网网址檚 the kind of thing that can happen when you get a whole lot of people who are using liquid stock markets to gamble the way they would in betting on race horses,B次元官网网址� Munger said.

The remarks didnB次元官网网址檛 win Munger many admirers on WallStreetBets. One Redditor posted a chart in the forum showing the spike in GameStopB次元官网网址檚 shares, adding: B次元官网网址淭AKE THAT CHARLIE MUNGER.B次元官网网址�