2015's IPO slowdown by the numbers

Traders on the floor of the New York Stock Exchange
Spencer Platt | Getty Images
Traders on the floor of the New York Stock Exchange

Just how bad was the IPO freeze of 2015? Public offerings were fewer and smaller, new data confirmed Tuesday.

Only 51 IPOs priced in the second half of 2015, the smallest batch since 2012, according to Proskauer's Capital Market Group 2016 IPO study. Not only did pricings slow down, but the annual aggregate deal value of $30.1 billion was the lowest since 2009, with companies seeing "down rounds" and fewer "mega IPOs," the report found.

Proskauer analyzed 309 IPOs that priced between 2013 and 2015, looking for patterns amid insider buying, terms, industries, underwriting costs and regulatory comments, among other trends. Researchers found that stock market volatility, interest rate change speculation, low energy prices and geopolitical concerns around Greece and China combined to dampen the traditional avenue by which start-ups become publicly traded.

As a result, only two so-called mega IPOs — raising proceeds of $1 billion or more — priced in 2015, compared with 16 in 2014. And many companies saw down rounds in 2015, where the public valuation of the company's stock is below its private valuation.

The report follows similar reports by firms like Renaissance Capital and after companies including Pure Storage and Atlassian have dipped below their recent IPO prices. Renaissance's IPO ETF, a basket of recent IPOs, is down 22.6 percent over the past year.

The 2015 slowdown has trickled into 2016, with only four pricing this year, the report said. But there's one silver lining: New regulations in the JOBS act give companies still planning to file this year more flexibility, the report said.

While the IPO drought has gone on too long, it might be a good thing that uncertainty in the markets forced start-ups to rethink their cost structures before going public, said Manuel Henriquez, founder, chairman and CEO of Hercules Technology Growth Capital.

"I do think when the IPO market does return back, you're going to see a lot better upside in those stocks, having adjusted their valuations privately," Henriquez told CNBC's "Squawk Alley" on Tuesday.

— CNBC's Arjun Kharpal contributed to this report.