Marijuana producer Green Growth Brands Inc. GGBXF, -7.40% has presented a formal offer to acquire Aphria Inc. APHA, +0.42% APHA, +0.32% to shareholders, a source familiar with the matter said Tuesday over the phone. MarketWatch could not immediately determine the offer's details. Previously Green Growth had said its bid valued Aphria at C$11 a share or roughly $2.1 billion. Regulators in Canada halted trading of both stock, though Aphria's U.S. listing on the New York Stock Exchange continued to trade in the extended session. Green Growth shares closed up 6.9% Tuesday as Aphria stock gained 6%. The ETFMG Alternative Harvest ETF s[: mj], which tracks a basket of pot stocks, fell 0.3% Tuesday.