It was all about the green at this week's Cannabis World Congress in New York.

That's the green of money, not marijuana leaves.

Exhibitors showing off hemp oils, vaping devices, edibles and a lot more were on display, but the most popular attendee could have been Rob Hunt, a partner at Tuatara Capital. He's the guy who writes the checks to fund development of cannabis products. Tuatara Capital is a private equity company launched last year to make cannabis-related investments.

"Last year alone there was $5.8 billion in legal cannabis sales in the United States," explained Hunt. "That number is expected to top $10 billion in two years. You're talking about a $75 billion dollar plus industry by 2020." 

Tuatara Capital focuses on four main investment areas: cultivation, processing, research and testing, and consumer retail.

"The companies that we think are really exciting are the ones that are thinking about a forward-thinking drug development pipeline that can be acquisition targets for your Mercks (MRK) - Get Report , your Pfizers (PFE) - Get Report and Novartis (NVS) - Get Report ," said Hunt, who added that he doesn't see that happening right away.

Hunt also expects to see the equity markets open up over time for cannabis companies. "Currently we don't look at a lot of companies we're working with as near-term IPOS, but at the same time our expectations are within three or four years this will change drastically," said Hunt. "We think the landscape is evolving quickly." 

Hunt said Tuatara Capital is very selective when it comes to where to invest.

"Certain states we think are really important for investment right now. Other states we wouldn't touch with a 10-foot pole," said Hunt. "Colorado is a great bellwether to get other states to realize you can do this in a sensible fashion. When Colorado came online, everyone was expecting it to fail, and there were a lot of people wishing it would."

Now, Hunt said, other states are using Colorado as a model on which to pattern their own regulations.