Constellation Brands Inc. (STZ ), the company behind Corona beer, is increasing its investment in Canadian marijuana company Canopy Growth Corp. (CGC) announcing it has invested $4 billion to acquire 104.5 million shares.

In a press release, the company said that with the increased investment it now owns 38% of the company. It paid C$48.60 per share for the new shares which represents a 51.2% premium to the stocks closing price Wednesday. Recently Canopy was up 22.3% or $5.49 to $30.11.

Constellation’s Investment Largest to Date for Pot Company

According to Constellation, the investment marks the largest one in a cannabis company to date and will provide Canopy with cash to build and or acquire assets so that it can expand globally in the close to 30 countries it said is pursuing a government-approved medical cannabis program. The proceeds will also go to lay the groundwork to go after new recreational pot markets including in Canada. (See also: This Is the First Fortune 500 Marijuana Stock.)

“Through this investment, we are selecting Canopy Growth as our exclusive global cannabis partner,” said Constellation CEO Rob Sands in a press release announcing the investment.  “Over the past year, we’ve come to better understand the cannabis market, the tremendous growth opportunity it presents, and Canopy’s market-leading capabilities in this space. We look forward to supporting Canopy as they extend their recognized global leadership position in the medical and recreational cannabis space.” Last year Constellation purchased a 10% stake in Canopy Growth.

Beer & Spirits Firms Look to Diversify

Constellation is among the beer and spirits companies that are looking to diversify into cannabis as their core businesses slow. Earlier this month, Molson Coors Brewing Co. (TAP) announced it is partnering with Hydropothecary Corp. to develop non-alcoholic, cannabis-infused beverages. The joint venture between the Canadian cannabis products maker and Molson Coors Canada, the company’s Canadian unit, will be structured as a standalone company. (See also: Coors Plans Cannabis-Infused Beverages in Canada.)

According to Bloomberg, Canada, which in October will become the first of the G-7 countries to make recreational use of pot legal, is expected to have pot sales of $4.9 billion by 2020 with spending on marijuana hitting $32 billion on a global basis in the same time frame. Bloomberg cited data from Arcview Market Research and BDS Analytics, two research firms.

“Our business can now make the strategic investments required to accelerate our market position globally,” said Bruce Linton, Chair, and Co-CEO, Canopy Growth said in the same press release about the investment.  “Constellation’s concentration of global cannabis activities exclusively through Canopy, coupled with the investment and its expert capabilities in brand-building, marketing, consumer insights and M&A will be a huge benefit as we look to expand our portfolio in Canada, the United States and emerging cannabis markets around the globe. ” As part of the deal Constellation will get to nominate four directors to Canopy’s board.