After-Hours Stock Movers:

AMC Entertainment (NYSE: AMC) rose 17%, extending gains after surging 78% during the regular session amid a rally in so-called meme stocks.

GameStop (NYSE: GME) rose 5% after climbing 74% intraday after a tweet by influencer "Roaring Kitty" signaled the meme stock rally is back.

Novavax (NASDAQ: NVAX) rose 2% after climbing 48% earlier today amid a mixture of excitement about its recent pact with Sanofi (NASDAQ: SNY) and short covering.

StoneCo (NASDAQ: STNE) fell 6% after reporting EPS and revenue that trailed estimates in the first quarter.

Fulcrum Therapeutics Inc. (NASDAQ: FULC) rose 6% after analysts at Goldman upgraded coverage on the stock to 'buy' from 'neutral'.

Merchants Bancorp (NASDAQ: MBIN) fell 2% after it launched an underwritten public offering of 2,400,000 shares of its common stock.

Jamf Holding Corp. (NASDAQ: JAMF) fell 2% after the commencement of an underwritten public offering of its common stock by investment funds affiliated with Vista Equity Partners. The selling stockholders are offering 8,956,522 shares.