(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) (THE CONVERSATION) You’ve heard of Big Pharma and Big Tobacco. How about Big Marijuana? The drug’s growing legalization is raising concerns among small-scale marijuana farmers and retailers that the corporatization of weed may be right around the corner. For example, earlier this year NASDAQ became the first major U.S. stock exchange to list shares of a marijuana production company.