I haven't done any volatility trading at all, so I'm going to ask a few (probably) stupid questions: UVXY is the Proshares short-term VIX ETF, which is very liquid. If you look at the price performance since inception, you can see that it very consistently declines in price. True, there are a few occasions when its price doubles or even triples (when VIX spikes), but in the long run, this ETF is basically designed to go down in price. First, is there something that prevents you from shorting this ETF? I think there was a simple explanation. but I don't recall it immediately. I don't mean be short risking all your capital, but even a tiny part of a portfolio short UVXY should give you a relatively steady source of return each year, no? This seems like an automatic money making machine, so please tell me what I am missing here. Second, there is an ETF which is almost the inverse of the aforementioned, namely, SVXY, which should give you the effect of shorting VIX without actually short selling any instrument. However, if you look at SVXY price graph, there is a very large drop in January 2018 when the market crashed. Can you explain why this happened with SVXY, but UVXY did not get as big of an upside? What is different here compared to just short selling UVXY? Thanks!