Updated from 3:37 p.m. EST

U.S. banks and savings and loan institutions posted a combined net loss of $26.2 billion during the fourth quarter, for the industry's first combined loss since the fourth quarter of 1990, according to the Federal Deposit Insurance Corp.'s Quarterly Banking Profile.

The FDIC also reported that its problem bank list grew to 252 institutions, up from 171 in September and 76 at the end of 2007.

The dismal numbers should not come as a huge surprise, but they illustrate just how bad the worst banking environment in a generation has been.

In comparison, the industry earned $1.7 billion in the third quarter and essentially broke even in the fourth quarter of 2007, with combined earnings of $575 million, according to the FDIC.

As expected, provisions for loan loss reserves drove the losses, with provisions totaling $69.3 billion during the fourth quarter, up from $50.5 billion in the third quarter and more than double the $32.1 billion set aside for reserves in the fourth quarter of 2007.

The FDIC noted that four large institutions accounted for half of the total industry's losses. Here are the 20 banks and thrifts with the largest fourth-quarter losses. Please note, these figures are for the banks and thrifts themselves, not the holding companies:

The problem bank list grew hand-in-hand with the number of banks and thrifts that were not

well-capitalized

, which numbered 202, up from 161 in September and 106 at the end of 2007, according to data supplied by Highline Financial.

TheStreet.com

recently published a list of

undercapitalized thrifts

, which included an updated list of 40 undercapitalized banks.

The FDIC's bank insurance fund totaled $18.9 billion, a decline of $15.7 billion during the quarter, as the agency handled twelve bank failures. Following is an interactive map with all 39 bank failures since the beginning of 2008:

Philip W. van Doorn joined TheStreet.com Ratings., Inc., in February 2007. He is the senior analyst responsible for assigning financial strength ratings to banks and savings and loan institutions. He also comments on industry and regulatory trends. Mr. van Doorn has fifteen years experience, having served as a loan operations officer at Riverside National Bank in Fort Pierce, Florida, and as a credit analyst at the Federal Home Loan Bank of New York, where he monitored banks in New York, New Jersey and Puerto Rico. Mr. van Doorn has additional experience in the mutual fund and computer software industries. He holds a Bachelor of Science in business administration from Long Island University.