The Wakefield-based marijuana company Curaleaf announced Wednesday that it had signed an agreement to acquire the Illinois-based Grassroots. It is part of a continued expansion that Curaleaf says has made it the largest marijuana company in the world based on revenue, and the largest operational marijuana company in the U.S.

The deal includes cash and stock and is valued at $875 million.

Curaleaf already operates in 12 states, and the expansion will give it operations in 19 states. Curaleaf today is a $3.8 billion company, while Grassroots is valued at $708 million.

Curaleaf’s 2018 revenues were $227 million, while Grassroots had 2018 revenues of $28 million.

Curaleaf is one of the biggest players in the U.S. marijuana industry, with 48 dispensaries, 13 cultivation sites and 12 processing sites across a dozen states.

Once the acquisition of Grassroots is complete, the company will have 68 operating dispensaries, 26 processing and 20 cultivation facilities, with licenses to open up to 131 dispensaries.

Curaleaf owns brands of hemp products and CBD-infused products for pets.

This year, Curaleaf has also purchased marijuana companies in California, Nevada, Arizona and Ohio.

In Massachusetts, Curaleaf has medical marijuana dispensaries open in Hanover and Oxford.

On the recreational side, the company wants to open three recreational stores. So far, it has received a provisional license from the Cannabis Control Commission to sell recreational marijuana from its Oxford dispensary.

The company also holds a provisional license to grow marijuana and manufacture products in Webster. It has not yet received any final licenses.

Grassroots does not hold any Massachusetts licenses. It operates in Illinois, Nevada, Pennsylvania, Michigan, Maryland, Oklahoma, Ohio, Vermont, North Dakota, Arkansas and Connecticut.

Illinois will legalize recreational marijuana Jan. 1, 2020. Illinois and Pennsylvania are both expected to be huge marijuana markets due to their large populations.

After the merger, Curaleaf’s revenues are expected to be nearly double that of its closest U.S. competitor, according to a slideshow provided to investors.

"With the acquisition of Grassroots and the pending acquisition of (marijuana product brand) Select, Curaleaf is the world's largest cannabis company by both revenue and operating presence," said Joseph Lusardi, CEO of Curaleaf, in a statement. "With a combined 68 open dispensaries, this transaction significantly accelerates our expansion strategy and strengthens our reach across the medical and adult-use markets.”

Mitch Kahn, co-founder and CEO of Grassroots, said in a statement, "This acquisition will enable us to give our patients and retail partners greater access to products that adhere to the highest standards of quality and reliability, and our employees the opportunity to be part of a best-in-class operator."

The sale is expected to close in early 2020.

Separately on Wednesday, the Cannabis Control Commission deferred considering a request by Curaleaf to approve its change of ownership application.

The company in October 2018 went public on the Canadian Securities Exchange, with some changes in the ownership structure compared to when it had applied for the Massachusetts license.

Under state law, Curaleaf was required to notify the commission of the change and get permission, but it did not do so.

According to commission staff, the company was not aware that the transaction required notification. The commission was also still developing its change of ownership process. Curaleaf submitted the change in ownership application after being notified that it violated state rules, in order to come into compliance.

After some discussion, commissioners decided to defer the discussion until August. “We’re not accusing anybody of operating in bad faith,” said Chairman Steven Hoffman. “This is complicated. We need time to work it through and get it right.”