Canada’s largest province is set to unveil a new law this week that will shape the future of cannabis legalization in Ontario, sources told MarketWatch on Tuesday, addressing the open question about how the substance will be sold in retail shops in the country’s most populous province.

Ontario has not yet created guidelines for how cannabis will be sold in brick-and-mortar retail shops, unlike the other Canadian provinces. The new law is set to define who can enter the market and where they will be allowed to sell cannabis in the country’s largest city, Toronto, and the rest of the region, according to people in Ontario who are familiar with the cannabis legislation.

The provincial government plans to make some details of the law public Wednesday and introduce the text of the bill in provincial parliament Thursday, two of the people said. Both announcements are expected after stock markets close on the East Coast.

Among the provisions in the legislation is a framework for obtaining licenses for retail cannabis sales that requires various entities to apply instead of employing an auction system that was rumored as an alternative, three sources said. The legislation will also include a “one-time” opt-out clause for municipalities that don’t wish to allow cannabis sales within their boundaries, three of the people familiar with the forthcoming law said. It was not immediately clear how much time municipalities would be given to exercise the opt-out option.

The conservative government has previously said that retail sales will begin in April 2019, and that it plans to operate the Ontario Cannabis Store, an online option to buy marijuana, after adult recreational use is officially legalized on Oct. 17. The Ontario government, under the leadership of Premier Doug Ford, abandoned the previous administration’s plan to sell cannabis via state-run liquor stores in favor of private retailers.

MarketWatch was unable to determine how many licenses would be available or what criteria the province would take into account when granting one. The Ontario minister of finance Victor Fedeli has previously said that the province will remain a wholesaler to the private retail entities. A spokesman for Fedeli said that the government did not plan to introduce the bill on Wednesday, but did not respond to several phone calls and emails seeking more information.

Ontario used $2.23 billion worth of cannabis in 2017, according to Statistics Canada, more than 40% of the total for the country. The government agency has estimated that Canadians will spend about $1 billion on pot during the fourth quarter, once the drug is legal for adult use.

Stocks of major cannabis producers such as Aurora Cannabis Inc.ACB, -4.54% ACBFF, -4.49%  — which reported earnings Monday— Canopy Growth Corp. WEED, -0.89% CGC, -0.46%  and Cronos Group Inc. CRON, -1.17% have been rampaging ahead of Canada’s official start date for legalizing cannabis. One of the most volatile names, Tilray Inc. TLRY, -0.39%  rose 8.1% in Tuesday trading, halting a three-day slide.

The Horizons Marijuana Life Sciences Index exchange-traded fundHMMJ, -1.54%   has gained 16.2% this year, while the S&P 500 index SPX, -0.33%  has increased 9.1%.