Originally Published: 23 MAR 22 11:11 ET

Updated: 23 MAR 22 13:03 ET

By Paul R. La Monica, CNN Business

(CNN) -- The meme stocks are back.

Shares of GameStop and AMC, two companies beloved by traders on Reddit and other social media platforms, are surging again.

Shares of GameStop rose more than 30% Tuesday and were up another 16% Wednesday. AMC soared 15% Tuesday and gained 20% Wednesday.

GameStop popped after the company's board chairman Ryan Cohen, co-founder of online pet supplies retailer Chewy, bought another 100,000 shares. "I put my money where my mouth is," he tweeted Tuesday. His RC Ventures now owns 9.1 million shares, an 11.9% stake in the retailer.

Cohen disclosed in a Securities and Exchange Commission filing that he bought the GameStop shares Tuesday at a price range of $96.81 to $108.82. The stock closed Tuesday at $123.14 and was trading at around $143 per share Wednesday afternoon.

Cohen is hoping to turn GameStop around with investments in NFTs and other cryptocurrency and blockchain initiatives. He has brought in two former Amazon executives to be the new CEO and chief financial officer. (Cohen is also pushing for changes at struggling retailer Bed Bath & Beyond. His firm has recently taken an activist stake.)

AMC is benefiting from some executive chatter on Twitter as well.

The theater chain's CEO, Adam Aron, tweeted Tuesday about his excitement for the upcoming spring and summer movie slate and defended the company's recent purchase of a more than 20% stake in gold and silver miner Hycroft.

"So amusing. Narrow-minded call our Hycroft investment... 'stupid'...'idiotic.' AMC so understands how to raise cash and stretch out debt," Aron wrote, referring to his company's recent plans to refinance.

"Tons of crow eating ahead, and it won't be by me!" the CEO added.

Both GameStop and AMC have fallen this year, along with the broader market. AMC shares are still down nearly 20% in 2022, despite a nearly 45% surge in the past five days. GameStop's stock has fallen about 3% this year, even after skyrocketing 65% in the past week.

Individual investors on Reddit aren't the only ones trying to cash in on the AMC and GameStop frenzy. Those stocks are top holdings in a meme ETF run by investment firm Roundhill. The ticker symbol? MEME, naturally.

The companies are also top stocks in a VanEck ETF that tracks social sentiment and trades under the ticker symbol BUZZ. Both funds are down about 20% this year, but have rallied sharply in recent days.