The bullish craze surrounding marijuana stocks has led an increasing number of investors to pile into one U.S.-listed exchange-traded fund (ETF) that tracks both Canadian (61%) and American (26%) companies.

Bloomberg reported that the ETFMG Alternative Harvest ETF (MJ) has taken in about $22 million in August, putting it on track for the largest monthly inflow since February. The fund is also August's top performer, according to ETF.com.

MJ’s recent outperformance comes as liquor producers show growing interest in selling pot ahead of the legalization of cannabis for recreational use in Canada. In the last month, some of the world’s largest alcohol companies have either bought significant stakes in marijuana firms or indicated an interest in partnering up with them, lifting the shares of many of MJ’s core holdings.

The ETF’s largest holding, Canopy Growth Corp. (CGC), has proved to be particularly popular with investors. On Aug. 15, Constellation Brands Inc. (STZ) invested $3.8 billion to increase its stake in the Canadian marijuana maker up to 38%.

Since that deal, the biggest yet in the industry, was announced, Bloomberg reported that the BI Canada Cannabis Competitive Peers index has gained more than 30 percent. (See also: Constellation Invests Additional $4B in Pot Grower.)

Marijuana stocks have also been boosted by news of a joint venture between Molson Coors Brewing Co. (TAP) and Hydropothecary Corp. (HEXO) to develop non-alcoholic, cannabis-infused beverages and recent reports that Smirnoff- and Johnnie Walker-maker Diageo PLC. (DEO) was in talks with at least three Canadian pot companies about buying a stake or forming a partnership.

“This reinforces the interest among large consumer companies in partnering with cannabis producers,” said Bloomberg Intelligence analyst Kenneth Shea. “It also signifies the confidence that consumer companies have for the continued rise in consumer demand for legal cannabis-infused beverages in Canada, but also eventually in the U.S. and in international markets.”

One of the biggest beneficiaries of growing speculation that alcohol producers are keen to team up with pot stocks is Cronos Group Inc. (CRON), MJ’s second-largest holding. When news of Diageo’s intentions were revealed, the Toronto, Canada-based company’s shares surged over 20%, according to Forbes.

Backing the Right Stocks

The fate of other ETFs tracking the Canadian pot industry indicates that MJ’s success is down to its backing of the right stocks. Not all marijuana producers have rallied in recent months, leading some of the sector’s other ETFs to struggle in comparison. (See also: Pot Stocks at Bitcoin Levels, Go Short Tilray: Jason Spatafora.)

Bloomberg claimed that one of MJ’s Canada-listed counterparts, the $703 billion Horizons Marijuana Life Sciences Index ETF (HMMJ), is on track for its biggest month of outflows since it began trading in April 2017. $6.1 million reportedly left the fund this month, including $5.1 million on Tuesday alone.