WASHINGTON ( TheStreet) -- Regulators shuttered eight banks Friday, bringing this year's tally of failed banks and thrifts to 50.

All of the failed institutions were included in TheStreet.com's list of undercapitalized banks.

TD Bank Buys Three Florida Institutions

The largest institution to fail Friday was Riverside National Bank of Florida of Fort Pierce, which had $3.42 billion in total assets when it was shut down by the Office of the Comptroller of the Currency. The Federal Deposit Insurance Corp. was appointed receiver and arranged for TD Bank, NA of Wilmington, Del., to take over the failed bank and its 58 offices.

TD Bank, NA is the main U.S. subsidiary of Toronto-Dominion Bank ( TD).

Riverside was the subject of rumors earlier in the week, when local competitor Seacoast Banking Corp. ( SBCF) of Stuart, Fla., raised $50 million through a preferred offering, with another $200 million pledged by private equity investors to fund the possible government-assisted acquisition of one or more failed banks. Local news reports listed Riverside as a possible target for Seacoast.

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The two other Florida failures on Friday included AmericanFirst Bank of Clermont, which was closed by state regulators and had $91 million in total assets, and First Federal Bank of North Florida, which had $393 million in total assets and was closed by the Office of Thrift Supervision. The FDIC also arranged for these to be taken over by TD Bank, NA.

The offices of the three failed Florida institutions were set to reopen during normal business hours as branches of TD Bank, NA, beginning Saturday.

The FDIC entered into a loss-sharing agreement on $2.2 billion of the assets acquired by TD Bank, NA, agreeing initially to share in 50% of losses on the acquired assets. The agency estimated the cost to the deposit insurance fund for the three failures would total $508.3 million, including $491.8 million for Riverside, $10.5 million for American First and $6 million for First Federal.

Lakeside Community Bank

The Michigan Office of Financial and Insurance Regulation closed Lakeside Community Bank of Sterling Heights, Mich. Since the FDIC was unable to find a buyer for the failed bank, the agency announced that checks would be mailed to customers on Monday for their insured deposit balances, except for customers with brokered deposits. For these customers, funds would be wired directly to brokers once the brokers provided documentation to the FDIC. The agency didn't say whether any deposits exceeded insurance limits. The cost to the deposit insurance fund was estimated to be $11.2 million.

Butler Bank

State regulators in Massachusetts shut down Butler Bank of Lowell, Mass., which was the first institution to fail in the state since the nation's banking crisis began in 2008. Butler Bank had $268 million in total assets, and the FDIC arranged for the institution to be acquired by People's United Bank of Bridgeport, Conn., the main subsidiary of People's United Financial ( PBCT).

When People's United announced its first-quarter earnings results on Thursday, CEO Philip Sherringham had said the company was pursuing acquisitions.

The FDIC agreed to share in losses on $206 million of the assets acquired by People's United and estimated to the cost to the insurance fund would be $22.9 million. Butler Bank's four offices were scheduled to reopen during normal business hours Saturday as People's United branches.

Innovative Bank

The California Department of Financial Institutions closed Innovative Bank of Oakland, Calif. and appointed the FDIC receiver. The FDIC sold the failed bank's $225 million in deposits for a 0.5% premium to Center Bank of Los Angeles, the main subsidiary of Center Financial ( CLFC). Center Bank also acquired the failed institution's $269 million in total assets, with the FDIC agreeing to share in losses on $178 million. The four Innovative branches were set to reopen Saturday as branches of Center Bank. The FDIC estimated the cost to the deposit insurance fund would be $37.8 million.

Tamalpais Bank

California bank regulators also shut down Tamalpais Bank of San Rafael, which was a subsidiary of Tamalpais Bancorp ( TAMB). The failed institution's $488 million in deposits were sold by the FDIC for a 2% premium to Union Bank, NA of San Francisco, which is held by Mitsubishi UFJ Financial ( MTU). In addition to the deposits, Union Bank, NA agreed to take on the failed bank's total assets of $629 million, with the FDIC sharing in losses on $522 million. The FDIC estimated the cost to the deposit insurance fund would be $81.1 million.

City Bank

The Washington Department of Financial institutions took over City Bank ( CTBK) of Lynnwood, Wash. The failed bank had $1.13 billion in total assets and was sold to Whidbey Island Bank of Coupeville, Wash., which paid a 1% premium for the failed bank's $1 billion in deposits.

Whidbey Island Bank is a subsidiary of Washington Banking Co. ( WBCO).

City Bank's eight branches were scheduled to reopen as Whidbey Island branches during normal business hours beginning Saturday. The FDIC agreed to share in losses on $456 million of the assets acquired by Whidbey Island Bank, and estimated the cost to the deposit insurance fund would be $323.4 million.

Ongoing Bank Failure Coverage

All previous bank and thrift failures since the beginning of 2008 are detailed in TheStreet.com's interactive bank failure map:

The bank failure map is color-coded, with states with the greatest number of failures highlighted in red, and states with no failures in gray. By hovering your mouse over a state you can see its total number of failures since 2008. Clicking on it will open a detailed map that pinpoints the locations of the state's failures and provides additional information about them.

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TheStreet.com Ratings issues independent and very conservative financial strength ratings on each of the nation's 8,500 banks and savings and loans. They are available at no charge on the Banks & Thrifts Screener.

-- Written by Philip van Doorn in Jupiter Fla.

-- At the time of publication, van Doorn held shares of Riverside Banking Co., the privately held holding company of Riverside National Bank of Florida, where he was previously employed.

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.