Trulieve (OTC:TCNNF), Green Thumb Industries (OTC:GTBIF), and GrowGeneration (NASDAQ:GRWG) have at least tripled investors' money over the past year alone. Those are substantial returns considering that the industry benchmark, the Horizons Marijuana Life Sciences ETF, only returned 22% over the past 12 months. Just what could be behind such amazing outperformance?