Tech IPOs Not Keeping Pace With VC Funding Surge Venture capitalists opened their wallets wide during the second quarter, but venture-backed initial public offerings fell.

If you're looking for signs of a tech bubble, you don't have to do much searching these days. From startup valuations and real estate prices to fancy perks and outlandish parties, practically everything in Silicon Valley is headed up and to the right.

A report Thursday from CB Insights shows that investor support, far from wavering, is still picking up, with venture capitalists plunging $13.9 billion into startups in the second quarter, the most in any period since 2001 and almost twice the amount from a year earlier. Investing in mobile surged to a record and the number of companies raising money at valuations of at least $1 billion was more than double the number that did so all of last year.

But the data reveal a dose of reality: The public markets are discerning. Venture-backed initial public offerings fell to 24 in the second quarter from 35 in the first as previously high-flying tech stocks came back down to Earth.

No matter how giddy investors are about the potential for the emerging class of Internet and mobile companies to disrupt the health-care, transportation, finance and education industries, public fund managers are seeking fully baked business models before taking the plunge. That wasn't the case during the 1990s tech bubble, when preproduct companies traded into the stratosphere before they came crashing down.

Read More: Venture financing in first quarter

"The IPO market is fairly rational," Anand Sanwal,chief executive officer of CB Insights, said in an interview. "Companies that don't have strong fundamentals are reticent to go out."

Even with the recent IPO dip, venture investors are making money, as the number of acquisitions of venture-backed companies rose 7 percent from the first quarter to 186, according to the CB Insights report. And there were some lofty prices, such as Apple's $3 billion purchase of Beats Electronics.

But to justify the private market valuations of companies like Uber, Airbnb and Dropbox—all in the 10 figures—investors need IPOs, and big ones. Late-stage deals in those startups as well as companies including Cloudera and Pinterest accounted for 45 percent of all venture funding in the first half of the year, while less than 20 percent of capital went to seed and Series A financings, the report shows. Much of the big money is coming from private equity firms, hedge funds and mutual funds, rather than traditional venture investors.

For all the talk of tech pockets emerging across the country and outside of Silicon Valley, California's share of venture financing continues to increase. The state attracted 64 percent of venture funding in the second quarter and saw more deals than the next 15 states combined.

"When it comes to the biggest tech companies that raise the biggest rounds of funding at the biggest valuations and the biggest exits, it's still happening in the valley," Sanwal said.