I thought that the "M"s were pink per this link - still don't know why they are saying that some are pink & some are grey - as of the time of this post, you need to go to page 4 for Sept 18 changes
If you bought at $25 and sold now, you can only write off a lousy $3K a year for next umpteen year come tax time. But once the bankruptcy becomes final, and the common becomes "WORTHLESS", then you can write off your ENTIRE loss in the year the stock became worthless.