I don't know much about stock markets, but the question I'd ask is whether it is in any way feasible to build up a short position that is "massive" on a scale t

I don't know much about stock markets, but the question I'd ask is whether it is in any way feasible to build up a short position that is "massive" on a scale that would be of interest to a Russian oligarch, as opposed to you or me, say, and whether it would be feasible to build up even a fairly tiny (for a Russian oligarch) short possition without it drawing a lot of attention.