A rose is a rose is a rose. Thank you Gertrude Stein for that observation. But a bank is not a bank is not a bank. That's because not all banks are serving the same market, nor are they all offering the same loans. If you're going to invest in banks, be sure you understand who they're lending to and what kind of loans they have on the books.

The first group of banks is community banks. As you might guess, they serve specific communities, usually within a fairly narrow geographic region. They rely on that region for their deposits with which they'll make loans, and loan demand. In other words, they serve a well-defined community. They know all the neighbors, participate in the local activities, have a high profile, hopefully do good things for a community.

Starting your own business? Need some extra space for your needlepoint habit? You're in luck ... office space comes cheap these days. In fact, rent for office space is sliding lower at the fastest rate since 1995. In the third quarter, office rents dropped 8.5% on a year-over-year basis.

Falling prices typically go hand in hand with falling demand and in fact, vacancies are on the rise as layoffs increase. New York-based real-estate research firm Reis says the office vacancy rate has hit a five-year high of 16.5%. Last quarter, tenants returned 19.6 million square feet of commercial rental space to their landlords.

The level of bad loans at US banks is getting worse and not better. According to the FT, "Sheila Bair, chairwoman of the Federal Deposit Insurance Corporation, said it was likely loan-loss provisions and bank failures would rise in coming quarters as the fallout from market turmoil hits the real economy."

Three banks have failed this year and the FDIC says the number of "problem" banks sits at 90.

All of this may be tough on regulators who may have to bail banks out, but it could be tougher on shareholders who have stock in mid-sized and regional banks. NCC (NYSE:NCC) has already had to raise $7 billion. Its shares are down to $5.68 from a 52-week high of $35.83. Other banks in the same category, such as Fifth Third (NASDAQ:FITB) and KeyCorp (NYSE:KEY), have lost about half their price compared to 52-week highs.

The news from the FDIC shows that investing in financial firms remains tricky and dangerous. It is not for the faint of heart.

Douglas A. McIntyre is an editor at 247wallst.com.