The marijuana industry is growing like a weed, and investors can't seem to get enough of pot stocks. Over the trailing-two-year period, the vast majority of marijuana stocks have risen by a triple- or quadruple-digit percentage.

But, truth be told, not a lot is definitively known about the weed industry, which still operates behind a cloud of uncertainty. After all, marijuana is still illegal in every country around the world, save for Uruguay. Within the U.S., despite 29 states having legalized cannabis in some capacity, the federal government maintains a Schedule I classification on the drug, meaning it's entirely illegal, prone to abuse, and has no recognized benefits.

Read more at The Motley Fool.