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Cramer: Is bull in trouble, again?

(Click for video linked to a searchable transcript of this Mad Money segment)

Jim Cramer has heard plenty of chatter about what might kill the bull. Usually he ignores it. This time he's worried.

"I'm always hearing talk of higher rates or the Fed," said Cramer.

Those often cited catalyst don't spook the "Mad Money" host. He believes modestly higher rates are a sign of economic recovery. That's good for stocks. Also, Cramer likes that the Fed has started to taper; he believes it's a sign the central bank sees prosperity ahead.

Nope, the typical bearish arguments don't worry Cramer.

But there is something.

Wall Street NYSE Bull
Adam Jeffery | CNBC

It involves two sectors of the market and the volume of recent IPOs "The sheer numbers of cloud and biotech IPOs make me very uncomfortable," Cramer said.

He worries they're a sign of froth.

That is, Cramer fears that investors have become so exuberant that they're assigning sky high P/E multiples to companies as they IPO, even though they may not grow into their valuations any time soon, if at all.

If the multiples were warranted Cramer thinks larger companies would have scooped up these smaller firms, before they came public.

"We've seen some aggressive acquisitions out there," noted Cramer. "Why didn't any of them snap up these companies before they IPO'd? For example, wouldn't IBM want Amber Road a cloud based software company that automates importing and exporting? That would seem to be a terrific gateway addition."

To Cramer the lack of M&A involving these small cloud and biotech companies suggests larger firms, in the same space, don't see the same value in theses companies as compared to the buyers of these stocks.

As a result, Cramer thinks many of these stocks may be seriously overbought "Remember, many of these firms are companies with no profits," Cramer explained.

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To make circumstances all the more perilous, Cramer says more shares of these newly public companies will come onto the market as locks-ups expire.

"I don't like that. I don't like that, at all. It's negative," Cramer said.

In fact, Cramer thinks the environment is eerily similar to the market environment, just before the Dotcom Bubble burst.

"This was just the way it was in 2000. We saw IPOs and secondaries that priced much higher than fundamentals warranted. Ultimately they sold very low."

These are the very circumstances that took down the bull 14 years ago. "Let's hope it doesn't happen again," said Cramer.

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