The S&P 500 Information Technology Sector has produced a return of 23.2 percent over the last year, and prominent hedge fund managers Doug Silverman and Rich Pzena see a bubble in the sector.

"I think biotech and other areas in tech have seen multiple expansions beyond any kind of reasonable cash flow expectations," Silverman, co-founder of Senator Investment Group, said at an industry event this week, according to CNBC.

"You can only call it a bubble, but I have not guessed when it will end."

Editor's Note: Secret Wall Street Calendar Uses Strange ‘Crash Alert System,’ Gets 18.79% Annual Returns

Pzena, founder of Pzena Investments, concurred.

"Yeah, I think we are in a bubble," he proclaimed, according to CNBC. "I don't know if I would say it's broadly in tech stocks. I think it's in certain stocks. But the hype feels like we're in another Internet-type bubble like 1999."

Pzena too said it's difficult to predict when the bubble will burst. "But what is predictable is that most of the companies won't grow into their multiples," he noted. "And shorting them with guts and not looking at the portfolio for three years is probably a smart thing to do."

But Morgan Stanley chief equity strategist Adam Parker scoffs at the bubble talk.

"We get why investors want to sniff out this bubble the day before everyone else and become rich and famous. That sounds awesome," he wrote in a commentary last week obtained by The Wall Street Journal.

"But, the truth is, portfolio managers typically want exposure to growth, and when you scan the list of the top 10 fastest revenue growth industries in the market in the next two years, Internet and catalog retail and Internet software and services are prominent among them."

Editor's Note: Secret Wall Street Calendar Uses Strange ‘Crash Alert System,’ Gets 18.79% Annual Returns

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