With due respect, there is nothing special about this embedded derivative relatively to other stocks. This is just to allow option play and just like any other stocks with option, they are prone to manipulation as making a stock go down when a call expires or stock go up when a put expirea.
But this has nothing to do with derivative or preferred stock, in particular anything to do with the past WAMU stocks as they are all extinguished. Let's put this to rest once for all, all WAMU stocks are extinguished and they are replaced by escrow markers and this is not a bad thing at all. Because all the Big Guys, hedge funds, TPS, Preferred, Common are all in ONE BASKET and if we get nothing then they will get NOTHING too.
Of course this is not going to happen.