In a report published ahead of the November election, analysts at Cowen and Co. estimated that the cannabis industry is worth about $6 billion in annual sales. Another $25 billion could be added to that from black market sales, and if and when those transition to the legal market, it could be worth $50 billion by 2026, the report found. Marijuana sales rose 30% in 2016 and Colorado, one of the industrys earliest U.S. test markets, generated $200 million of tax revenue from $1.3 billion in marijuana sales last year. But for all of the excitement about the rapid change in the industry of the past few years, there are still many obstacles to overcome and challenges that make investing a risky endeavor. Here are three issues to consider: Check out: Opinion: How investors can separate the winners from the losers in the marijuana industry Will they, wont they The biggest challenge for the marijuana industry is figuring out how the federal government will approach the industry and whether it will enforce federal laws, which continue to ban use of the plant. Marijuana is still labeled a Schedule I substance along with heroin and LSD, creating complications for growers and sellers in the states where it is legal. For now, the industry seems confident that public approval and expanded research will shield it from government interference, but that doesnt make critical comments from lawmakers any Marijuana Stocks less disconcerting.