In most if not all cases the answer is: they can't. The price of crypto, especially that of the ICO era, is propped up by the same individuals that would most want to sell it. It's their HODLing of the coin that keeps it illiquid enough to allow them to drive the price up to the ico target and beyond. By casing out they'd be selling largely to themselves + the thin wisp of actual rubes they've duped into believing there's any substantial buy support under the listed market price.
