Ackman said there are 150 private companies valued at more than $10 billion in value and that the top third meet his quality thresholds.

“We’re looking for a simple, predictable free cash flow-generative company, very high barriers to entry with minimal exposure to what we call risks, extrinsic risks we can’t control,” Ackman said. “We’re looking for the super durable great growth business that we can own for the next decade.”

Pershing Square Tontine Holdings Ltd., the largest-ever special purpose acquisition company, is now officially on the hunt for what it has called a “mature unicorn” as a merger candidate. Units of the blank-check company opened at $21.10 in New York trading, 5.5% above their IPO price of $20. The units were up 8.4% to $21.68 at 3:09 p.m.

Unicorns are usually defined as private companies valued at $1 billion or more, though Pershing Square Tontine Holdings has said it could look at businesses worth $10 billion or more.

Airbnb, Elon Musk

Ackman said he isn’t looking for energy companies that are bankrupt but “will certainly look at” businesses that will survive the coronavirus pandemic and become a strong player like Airbnb Inc., which has been in talks to go public.

“We don’t require the company today to be cash-flow positive on an overall basis,” he said.

Elon Musk’s space travel company SpaceX and secretive Silicon Valley firm Palantir Technologies Inc., which said it has filed confidentially for a public listing are also on Ackman’s radar.

“We have a lot of admiration for Elon Musk and what he has accomplished,” Ackman said.

Funds associated with his investment firm, Pershing Square Capital Management, have committed to deploy as much as $3 billion more to the vehicle, bringing the total funding as high as $7 billion, according to filings with the U.S. Securities and Exchange Commission.

Second SPAC

Pershing Tontine isn’t Ackman’s first blank-check company. Justice Holdings Ltd., which raised $1.44 billion in a 2011 listing in London, merged with Burger King Worldwide Inc. in 2012 and, in a deal with 3G Capital Inc. Burger King later merged with Tim Hortons Inc., creating Restaurant Brands International Inc.

SPAC listings have reached an all-time high, with more than $17.7 billion raised in the U.S. as of Wednesday.

Ackman isn’t going to do all the chasing though. He expects some potential targets to come knocking at the company’s door.

“If you’re an investment banker today, you’re going to call your favorite $10 billion company and say isn’t this an interesting way to go public,” Ackman said. “We welcome the inbound call.”