Tradeweb, which is backed by Blackstone and a collection of big banks, opened on the Nasdaq at more than $34 after a $27 initial price offering, a deal that Cramer said was "massively oversubscribed," and closed at less than $37 on Friday.
Although shares of Tradeweb are selling for roughly 31-times 2019 earnings estimates, MarketAxess, another electronic trading platform for bonds, is trading for 50-times earnings, he said.
"That makes Tradeweb seem like a bargain, especially when you consider that Tradeweb actually has a faster growth rate" than MarketAxess, the "Mad Money" host said.
Cramer said he likes Tradeweb's business because average daily volumes grew 37% last year and the company is already profitable, which is uncommon for an IPO. January was the company's best month in its more than 20 years of business. It could have topped that performance in February, if it wasn't a short month, he said.
The electronic marketplace operator also generates 48% of revenue from subscription fees, which is recurring revenue, and minimum volume floors. While it does not have the same growth rate as companies like Lyft, investors won't have to worry about how Tradeweb will make a profit, Cramer said.
"I've gotta tell you, I like this story," he said.
One cause for concern, however, is Tradeweb's complex ownership structure, Cramer noted. The company has four classes of shareholders, and class A shareholders, which includes the stocks sold in the IPO, have but a 2% total voting interest in the company.
"That means if you buy this stock, Blackstone and the banks are calling the shots and you're just along for the ride," Cramer said.
Still, Cramer said he understands why the IPO was such a big hit.
"After yesterday's monster move, the stock is far from cheap, but you've got my blessing to buy this one, although obviously at these prices a little more speculative," he said. Just be careful, buy it slowly — hopefully you'll get a pullback so you can get more in at an even better basis."