Despite Bank of America's (NYSE: BAC) announcement of expectations-beating earnings this morning, shareholders weren't exactly elated. After temporarily rising, shares ultimately sold off almost 5% by market close.

Why? Reported earnings for complex too-big-to-fails truly are an enigma wrapped in a fiction. Perhaps as much as any other industry, earnings per share at massive financial institutions are affected by so many one-time events and subjective modeling on a quarter-to-quarter basis that they alone can't tell the whole story.

Although B of A has indeed been improving thanks to better credit quality and lower expenses, and its latest quarter now makes the Dow (INDEX: ^DJI) eight for eight in earnings beats, there still are a number of areas that give B of A investors pause.

The bulk of this quarter's earnings improvement came from reduced mortgage banking losses and the lack of writedowns and legal settlement costs this quarter. But it's unlikely that the bank's mortgage troubles are completely behind it even after the company has set aside $35 billion to cover bad mortgages and put-back requests on mortgages that Fannie, Freddie, and private investors like BlackRock, PIMCO, and AIG (NYSE: AIG) have accused it of improperly underwriting. B of A isn't the only underwriter in hot water, but its acquisitions of Merrill Lynch and basket case Countrywide gave it more exposure than Wells Fargo (NYSE: WFC), Citigroup (NYSE: C), and JPMorgan Chase.

Bank of America is also continuing to suffer from the same sorts of top-line problems that have been plaguing much of the banking industry. Low interest rates, regulatory crackdowns, and the bursting of the finance bubble have meant less revenue for the sector.

That being said, at a price-to-book multiple of 0.6 and forward P/E of 10.6, the stock isn't exactly priced as though the behemoth will return to its prior level of profitability. That means there could be significant upside over the long term if the company is able to partially right itself.

If you want to know more about Bank of America, make sure to stay up to date with the latest analysis on the bank. You'll find it in our brand-new premium research report, which includes a comprehensive view of the opportunities and threats facing the global bank as well as a full year of updates to go with it. Get your report on Bank of America today.