The first marijuana exchange-traded fund has reached a milestone that has as much to do with surging pot stocks as it does with investor inflows.

“HMMJ’s growth has far exceeded our expectations as investors have strongly supported the sector in anticipation of Canada’s upcoming recreational marijuana legalization,” Horizons Chief Executive Officer Steve Hawkins said in a statement. Canada will legalize recreational use on Oct. 17.

Enthusiasm for the fund, whose assets total around $783 million in U.S. dollars, appears to have cooled somewhat last month, however, as investors pulled money out in six of the the seven trading days between Aug. 21 and Aug. 29. They withdrew a total of C$15.9 million over that stretch before plowing C$14.1 million back in on Aug. 30, bringing the month’s total inflows to C$12 million.

Meanwhile, buyers in the U.S. have been scooping up shares of the $436 million ETMG Alternative Harvest ETF, known by its ticker MJ. It took in more than $30 million August, its largest monthly inflow since January.

Pot stocks have been surging since mid-August, when Corona beer maker Constellation Brands Inc. invested C$5 billion in Canopy Growth Corp., a signal that mainstream companies are beginning to see the potential in cannabis. Canopy, the second-largest holding in HMMJ, has seen its stock price more than double since the deal was announced. HMMJ has gained 54 percent over the same period.

HMMJ invests in life sciences companies with significant activities in the marijuana industry. Its holdings include major cannabis producers as well as ancillary businesses like Scotts Miracle-Gro Co.