Startups are not going public at the same rate they did a decade ago.

The number of public companies in the U.S. dropped 52 percent by 2016 from its peak a decade earlier, The New York Times reports. The shift is ascribed to different factors, including a volatile market and availability of larger funding rounds from venture capital investors, known as mega-rounds, which allow companies to stay private longer. Big corporations are also scooping up and acquiring startups days--or even hours--before their planned IPOs, in part to deter competition from up-and-coming firms.  

"What would have happened to Instagram if Facebook hadn't bought them?" Thomas Philippon, a professor of economics at New York University told the Times. "They would have competed with Facebook for sure." 

Earlier this month, SAP acquired survey software maker Qualtrics for $8 billion, only a few days before it was set to go public on the Nasdaq. In June, Workday acquired Adaptive Insights, a financial planning startup, two days before its planned IPO, and in 2017, Cisco bought software analytics startup AppDynamics for $3.7 billion--the night before it was scheduled to go public.

Even companies that have already gone public are getting scooped. In March, Salesforce spent $6.5 billion to acquire MuleSoft, a business software company that went public in 2017. The number was nearly a third more than its public market cap at the time.

Business leaders including LinkedIn founder Reid Hoffman and venture capitalist Marc Andreessen have proposed a new market exchange to persuade companies to go public. The Long-Term Stock Exchange (LTSE) would let shareholders accrue more voting power the longer they own a company's stock. The goal is to encourage long-term, strategic planning instead of short-term results, which could make it more attractive for founders to explore the public market. However, the plans just hit a snag, with the SEC commissioner Robert Jackson Jr. casting doubts about the proposed structure, The Wall Street Journal reports.

Eric Ries, author of The Lean Startup and LTSE founder and CEO, is not changing course, however. He told the WSJ that he would file LTSE's application to launch its own exchange before the end of the year. After that, the SEC will have up to 240 days to issue its ruling.