Regulators on Friday shut down banks in Florida, Arizona and Kansas, bringing to 133 the number of U.S. banks that have failed to hold up this year against the struggling economy and a cascade of loan defaults.

The Federal Deposit Insurance Corp. took over Miami-based Republic Federal Bank, with $433 million in assets and $352.7 million in deposits. A bank based in Boca Raton, Fla., 1st United Bank, agreed to assume all the deposits and $267.1 million of the assets of the failed bank. The FDIC will retain the rest for eventual sale.

In addition, the FDIC and 1st United Bank agreed to share losses on $210.4 million of Republic Federal's loans and other assets.

The FDIC also took over Valley Capital Bank, based in Mesa, Ariz., with $40.3 million in assets and $41.3 million in deposits; and SolutionsBank in Overland Park, Kans., with $511.1 million in assets and $421.3 million in deposits.

Enterprise Bank & Trust, based in Clayton, Mo., agreed to assume the assets and deposits of Valley Capital, while Arvest Bank, based in Fayetteville, Ark., is buying the assets and deposits of SolutionsBank.

The FDIC also agreed with Enterprise Bank to share losses on $29.8 million of Valley Capital's assets, and agreed with Arvest Bank to share losses on $411.3 million of SolutionsBank's assets.

The FDIC estimates the failure of Republic Federal will cost the deposit insurance fund $122.6 million; the failure of Valley Capital an estimated $7.4 million; and the failure of SolutionsBank an estimated $122.1 million.

The shutdown of Republic Federal brought to 13 the number of bank failures in Florida so far this year. Failures also have been concentrated in California, Georgia and Illinois.

Last week saw the failure of Ohio's AmTrust Bank, the fourth-largest bank to fail this year, with about $12 billion in assets and $8 billion in deposits. The Cleveland-based bank's failure is expected to cost the federal deposit insurance fund an estimated $2 billion.

As the economy has soured, with unemployment rising, home prices tumbling and loan defaults soaring, bank failures have accelerated and sapped billions out of the federal deposit insurance fund. It has fallen into the red.

The 133 bank failures are the most in a year since 1992 at the height of the savings-and-loan crisis. They have cost the federal deposit insurance fund more than $28 billion so far this year. They compare with 25 last year and three in 2007.

The FDIC expects the cost of bank failures to grow to about $100 billion over the next four years.

Depositors' money _ insured up to $250,000 per account _ is not at risk, with the FDIC backed by the government.