Robinhood Markets Inc. (NASDAQ:HOOD) has been a hot topic in the stock market lately, with its shares soaring after the company announced a new credit card. However, CNBC's Jim Cramer has some reservations.

What Happened: Cramer expressed his concerns about the rapid surge in Robinhood's stock price during CNBC's "Lightning Round" segment.

"I think that that Greyhound bus has left the station, and I got to wait. I mean, the thing just doubled in no time whatsoever...We don't buy doubles here."

Why It Matters: Robinhood's stock surge followed the company's announcement of its new credit card, the Robinhood Gold Card, at its first-ever keynote event. The credit card offers 3% cash back on all categories with no annual fees and no foreign transaction fees.

Robinhood's recent stock surge has been attributed to the company's expanding financial services offerings. Robinhood CEO Vlad Tenev stated that the company's goal is to create a financial world where all customer assets are held at Robinhood, and all financial transactions go through the platform.

Despite the stock's recent performance, Cramer had previously voiced his concerns about the sustainability of Robinhood's growth. He attributed the stock's surge to "pure momentum" rather than the company's underlying business fundamentals.

Robinhood's stock price has been on a rollercoaster ride recently. On Wednesday, the stock closed 3.79% up at $20.01. The stock's 52-week high was $20.55, and its low was $7.91.

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