Should cannabis investors be buying stocks in the tobacco sector? Is now a good time to invest in pot stocks? How long should investors hold their pot stocks? These are just a few of the questions we ask Meb Faber, CEO and CIO of Cambria Investment Management.

The Motley Fool sat down with Faber to talk about Cambria Cannabis ETF (NYSEMKT:TOKE). The quant firm's low-cost cannabis fund seeks exposure to the broader marijuana industry with top holdings including GW Pharmaceuticals (NASDAQ:GWPH), Altria (NYSE:MO), and Canopy Growth (NASDAQ:CGC).

Corinne Cardina: Excellent. Last question before we have to let you go, we talked a little bit about timeline and you said investors should be ready to hang onto this for at least a decade to see the positive accumulation, but are there any other characteristics of investors that you think this ETF would be a good fit for, people who are looking more for growth or for value. Any thoughts there?

Meb Faber: All the different cannabis funds have different flavors and that's fine. Some people want exposure to the multi-state operators. Some people always has a tilt toward a little bit about tobacco. Do you know there's not a single tobacco fund in existence in the U.S.? Which I find to be very surprising. I think there's a lot of opportunity, those stocks, most they've been cut in half since 2017 too. Some of those on the barbell exposures sporting 5-10 percent yields. Yields in a world where I hear treasuries are less than one. Real quick about time horizon. I often talk to clients. We have over 60,000 investors and I talk to clients and they'll ask me something to talk about one of our funds and then would say, "Meb, I'll buy your fund, it's not doing well. I've held over six months. I'm going to give it a few more months. We'll see how it goes." I say, "Oh, no, it can get way worse than that." They laugh awkwardly and they're like, "Well, how long should I give it?" I used to say 10 years. They would laugh even more awkwardly thinking I'm joking. Now, I actually say 20 years. Let me explain why. If you're going to do an active approach, move away from the market cap weighted index, which is free, essentially free in 2020, it's about five basis points, to get a World Index. The new better be pretty weird and different, and have a long-term time horizon, and real quick, why? There's no more universally held belief and all of investing then stocks outperformed bonds. I don't know a single person that doesn't believe that. However, you asked most people how long would you be willing to give an asset underperforming? Most people said two to three years, and that's institutions too, by the way. Stocks at one point this year in March versus the long bond in the U.S. had gone 40 years of similar performance. That is insane if you think about most people were expecting, oh, no, I need my returns, I need them now. You thinking about something as crazy as cannabis, which is an extremely concentrated sector that's pretty small and then most people are thinking about next week, next month, forget about it. You guys have me back on in 2030. We'll do this again. It'll probably be on holograms or teleporting somewhere. But we'll talk about how cannabis has done then. Long-term perspective, put in the lockbox and put it away for a decade.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.