For Brendan Kennedy, Michael Blue and Christian Groh, raising money a few years ago was a real slog.

The reason was simple: Investors were wary of putting money behind a company that was involved in the marijuana industry.

But now, as cannabis use has become more accepted and a majority of Americans now favor legalization, the three founders of Seattle-based Privateer Holdings are rolling in the greens.

“I can’t say that we predicted everything to move this quickly,” said Kennedy, the company’s CEO.

Privateer Holdings, which had already raised $22 million, is now set to raise a Series B of more than $50 million. Kennedy told GeekWire that the round is not quite complete, but that he expects it to close next month.

Privateer is a private equity holding company that has acquired four marijuana-related companies in the past four years. They range from Seattle-based Leafly, a marijuana strain resource that was just nominated for GeekWire’s App of the Year, to Tilray, a startup Privateer founded in Canada that’s producing premium marijuana and selling it online.

The company has come a long way since 2010. It took Privateer 18 months to raise its first $7 million, funding that Kennedy said was the “most difficult money I’ve ever raised.”

Now, though, investors are showing serious interest. While the marijuana industry is still complicated on numerous levels — from legal to political to social issues — the use of cannabis is quickly becoming more mainstream, whether it’s Colorado opening up the first retail recreational marijuana stores to more and more states legalizing medical marijuana.

“Sometimes we talk about cannabis prohibition like the Berlin Wall, with each one of these events as another brick being thrown off the wall,” Kennedy said. “It’s making investors feel a lot more comfortable. They are also doing more research and evaluating different opportunities in the industry — the more research a potential investor does, the easier it is to close them.”

Privateer won’t name their investors, but the previous $22 million came from high net-worth individuals and small family offices. Kennedy, previously the COO at Silicon Valley Bank, said that because of the existing preconceptions about the marijuana industry, VC firms have never been willing to publicly make investments.

However, the $50 million-plus round that Privateer is about to raise includes several institutional investors.

“That will be a big milestone for the industry,” Kennedy said.

The 15-person Privateer team takes a “very hands-on” approach to the companies it acquires, which also include Arbormain, a Washington-based marijuana business park that licensed producers can rent space from, and Lafitte Ventures, a Canadian company making Tilray-branded marijuana.

“We structured the company in a way so we can incubate, build, invest and acquire — it just depends on the opportunity,” Kennedy said. “We really enjoy the flexibility to do any of those four things, and because of the unique industry, we have that flexibility.”

So far, Privateer’s investments seem promising. Leafly, for example, is seeing four million visits per month across its platforms and is growing traffic by 15 percent every month. The company also just partnered with Snoop Dogg for a 4/20 “Wellness Retreat” event in Seattle and Denver later this week.

Meanwhile, two months ago Privateer held a career fair for Tilray, the Canadian marijuana production company it now owns. It received more than 400 applications and expects to hire 80 employees by May — four months ago, the company did not have a single employee.

But this seems like only the beginning for a Seattle private equity firm that was struggling mightily to raise a few million bucks just two years ago.

“There are still massive hurdles and massive risks, but this industry is moving really quickly,” Kennedy said. “We just need to hold on and keep moving as fast as we possibly can to keep up.”