CHICAGO ( TheStreet) -- Illinois has had 12 banks fail so far this year, the most of any state except Georgia, with 16.

Still, an analysis of Illinois banks and thrifts by TheStreet.com Ratings identified 76 institutions that were in good shape as of March 31. The state has had so many failures, as well as successes, because there are so many banks and thrifts -- 645 -- as regulators allowed branch banking later than most other states. So the Land of Lincoln is lagging behind in the consolidation of its small banks. (See TheStreet.com's interactive Bank Failure Map for a summary of all failed banks and thrifts for 2008 and 2009.)

Strongest Illinois Banks and Thrifts

Based on March 31 financial reports, 76 Illinois institutions were rated B-plus (good) or higher, down from 80 the previous quarter.

Illinois Banks and S&Ls Rated B+ or Higher
Source: SNL Financial

The ratings encompass a large number of data, with the greatest weight on capital strength, credit quality and earnings stability. To be considered well-capitalized, most banks, and saving and loans need to maintain a total risk-based capital ratio of at least 10%.

Largest Illinois Institutions

The following table includes capital, earnings and asset-quality ratios for the 10 largest Illinois banks and thrifts.

10 Largest Illinois Banks and S&Ls
Source: SNL Financial

The highest-rated and largest bank among the 10 largest institutions in the state is Northern Trust Co. of Chicago, the main subsidiary of Northern Trust Corp. ( NTRS), which was assigned a B-minus (good) financial-strength rating.

The second-biggest is Harris NA, a subsidiary of Bank of Montreal ( BMO), which was rated C-minus (fair).

Two troubled banks among the 10 largest are Corus Bank NA, the main unit of Corus Bancshares ( CORS), and AMCORE Bank NA, held by AMCORE Financial ( AMFI). Both have E-minus (very weak) financial-strength ratings.

Corus Bank was undercapitalized as of March 31, and its holding company announced July 21 that it's revising the financial statements because loan-loss provisions had been underestimated $16 million. Corus had a nonperforming-asset ratio of 32.8% as of March 31 - meaning a third of all loans went sour -- and the holding company on May 1 warned that it could be placed into receivership by regulators.

AMCORE Financial said a month ago that regulators required AMCORE Bank to achieve and maintain a total risk-based capital ratio of at least 12% by Sept. 30. The bank was considered adequately capitalized as of March 31, with a risk-based capital ratio of 8.8%. It had a nonperforming-asset ratio of 7.8%.

Weakest Illinois Banks

Fifteen Illinois institutions were originally included in TheStreet.com's recent list of Undercapitalized Banks and Thrifts as of March 31. Seven have since failed, leaving eight undercapitalized institutions in the state. Of course, some may have raised capital since March 31, although that's a tall order amid the recession and more risk-averse investors.

There were 16 Illinois banks and thrifts with nonperforming-asset ratios of more than 10% as of March 31.

Free Bank and S&L Ratings

TheStreet.com Ratings issues independent and very conservative financial-strength ratings on the nation's 8,300 banks and savings and loans. These are available at no charge on the Bank & Thrift Ratings Screener.

-- Reported by Philip van Doorn in Jupiter, Fla. Feedback can be sent to philip.vandoorn@thestreet.com.
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.