Regulators closed four banks in the United States on Friday, including one in Colorado with over $1 billion in assets, bringing the total number of closures this year to 84.

The largest of the failed banks, the Community Banks of Colorado, had $1.38 billion in assets and $1.33 billion in total deposits as of June 30, the Federal Deposit Insurance Corp. said. It is the largest U.S. bank to fail since Aug. 19.

Bank Midwest N.A., Kansas City, Mo., agreed to assume all the deposits of Greenwood-based Community Banks of Colorado and to purchase essentially all of the assets. Its 40 branches will reopen Saturday as branches of Bank Midwest.

The Federal Reserve Board, which appointed the FDIC as the receiver of the Colorado-based bank, said it had been "critically undercapitalized" since July 29.

Two of the banks to fail on Friday were in Georgia, and one was in Florida.

In Georgia, regulators closed the Community Capital Bank in Jonesboro and Decatur First Bank in Decatur.

The State Bank and Trust Co., Macon, Ga., has agreed to assume the deposits and purchase essentially all of the assets of the Community Capital Bank, which had $181.2 million in assets the end of June. The State Bank and Trust Co. is a subsidiary of the State Bank Financial Corp.

Meanwhile, Fidelity Bank, Atlanta, agreed to assume all of the deposits and purchase essentially all of the assets of the Decatur First Bank. The failed bank had about $191.5 million in assets and $179.2 million in deposits at the end of June.

In Florida, regulators shut down the Old Harbor Bank in Clearwater, and entered into an agreement with 1st United Bank, Boca Raton, to assume the bank's deposits and purchase almost all of the assets. At the end of June, the Old Harbor Bank had $215.9 million in assets and $217.8 million in total deposits.

The four bank failures Friday cost the FDIC's insurance fund an estimated $358.8 million. The Colorado bank's failure made up the bulk of that cost with an estimated $224.9 million.

Most of the banks that have failed so far this year have had less than $1 billion in assets, illustrating the problems facing small banks.

However, FDIC officials expect there will be fewer failures this year than in 2010, when 157 banks were closed.

Separately, President Barack Obama announced Thursday that Thomas Hoenig, former CEO and president of the Federal Reserve Bank of Kansas City, has been nominated to become the new vice chairman of the FDIC.

(Reporting by Sarah N. Lynch and Dave Clarke; editing by Carol Bishopric)