I disagree. Buying after NWS does not automatically mean that the investor assumed that conventional, ages old investment laws would be followed. An investor who bought after the NWS might very well have read all the prospectuses and known that it is illegal for a senior shareholder to take 100% of profits and send zero to juniors and common. He might have expected also that, based on ages old FDIC laws, upon which the relevant GSE conservatorship was founded, would hold true and be controlling. Such an investor might also have believed that the gvt only wanted to accelerate the payback on its original 10% dividend by enacting the NWS because, as we all noticed, the GSEs were becoming profitable again, leading one to imagine that the conservatorship might end soon, what with a Dem controlled WH, where traditionally that party has been more sympathetic to the GSEs' cause. Such an investor might not think it would be realistically possible for the GSEs to be wound down without severe disruption, and that bo private capital would be able to backstop 30yr mortgages, and he might have assumed that the gvt would never be willing to ensure the elimination of the 30yr mortgage.
All of those things an investor who bought into shares after the NWS are very credible and realistic investment thesis, and certainly are equally feasible to the investment thesis you proposed as an argument agains post-NWS investors claims. You said basically "they should have reasonably known they'd get screwed" to paraphrase you. But even if that is true, there was no law that clearly proved that they would get screwed. So they invested with an understanding that the law would back them up, perhaps. We all know it hasn't so far, but there was certainly a good enough case to be made that the law MIGHT back them up, otherwise no one would have invested after the NWS at all!
