The brand new, massive “blank-check” company, led by billionaire activist investor Bill Ackman, is looking to "marry a unicorn."

Pershing Square’s Tontine Holdings (PSTH.U) raised an astonishing $4 billion from investors in its record-breaking debut on the New York Stock Exchange on Wednesday. Investors cheered the shares, which ended the first day of trading up 6.5%, closing at $21.30 per share.

It’s the latest in a string of special purpose acquisition companies (SPACs). These blank-check companies have been around for years, but garnered more after bringing companies like DraftKings (DKNG), Nikola (NKLA), and Virgin Galactic (SPCE) to the public markets — side-stepping the traditional initial public offering (IPO) route.

"Our thesis is by having a $5 billion cash pile in a public company; it's our own version of a unicorn. It's a one-of-a-kind entity,” Ackman told Yahoo Finance on Wednesday, following Tontine’s floatation.

“So, we're looking to marry a unicorn. So we're prettying ourselves up for the most attractive possible partner," he added.

At one time, the blank-check company model was associated with high risk, in a way that drew both regulatory scrutiny and some controversies.

However, Ackman defended the idea of a SPAC a “good one, which is: raise a cash shell, list it on an exchange, and then issue securities to take a private company public.”

He added: “It's a much more efficient process, a much less risky process for the private company."

The 54-year-old investor explained that a typical initial public offering (IPO) could take several months, during which companies are "under enormous scrutiny" that can distract from the business's day-to-day operations.

"The alternative with a SPAC is we work quietly with the senior-most people at the company. We learn about the business. We do our due diligence. We enter into a transaction, and the first press release is 'you're done,'" Ackman said — noting that it minimizes the distraction and uncertainty that comes with an IPO.

Not his first rodeo with SPACs

This isn't Ackman's first foray into the SPAC world.

In 2012, he used his shell company Justice Holdings, to buy Burger King and return the burger chain to the public markets. Today, Burger King is part of Restaurant Brands International (QSR) — Pershing Square's biggest equity holding, according to the most recent regulatory filing for the firm.

In the coming months, Tontine Holdings will look across four principal areas to pursue a deal, including examining companies that may have been discouraged from going the IPO route. Those have been hit by recent market volatility, or are venture capital-backed businesses with "significant scale, market share, competitive dominance and cashflow" that Ackman dubs "mature unicorns."