The talk about the FASB decision to relax mark-to-market accounting rules is seriously overblown. I do not think that this was a particularly good decision, but the idea that this will horribly spook investors, or that the FASB has given the banks permission to lie to us, is extravagently unlikely.
First of all, the banks have to disclose in the notes to their financial statements the size of the boost their balance sheet gets from the change in accounting rules. That will give investors a good guide to backing out that change--which is probably why Bloomberg reported this morning that Citibank isn't even bothering to make it.
If you can't or won't read the notes to a 10-K or 10-Q, you should not be investing in bank stocks. Let me put that another way. IF YOU CAN'T OR WON'T READ THE NOTES TO FINANCIAL STATEMENTS, YOU SHOULD NOT BE INVESTING DIRECTLY IN STOCKS. I really have no sympathy for anyone who decides to gamble on a bank stock right now without even basic financial literacy. They can hardly say they weren't warned that this is mighty dangerous behavior.
Second of all, the mark-to-market price is not the "true" price; it's a price in an extremely illiquid, and therefore fairly inefficient, market. The value the banks put on it isn't any more likely to be accurate, of course. But we're talking about swapping an optimistically biased inaccurate price for a pessimistically biased one, not The End of Accounting As We Know It.