He's referring to a substance that's still illegal under federal law, which means that large, federally insured banks don't handle marijuana transactions. Even while touting a potential $75 billion investment opportunity in a research note to investors, the New York bank Cowen Inc. warned that marijuana businesses "may be at risk of federal and/or state criminal prosecution."
In other words, marijuana investment is not for the weak of heart, or the sensitive of wallets. But for thrill-seekers and pioneers like Karban, Rafael de la Cruz and Arnaldo "AJ" Peralta, it is the space to be in.