SARASOTA — Federal banking regulators closed Century Bank of Sarasota today after the troubled financial institution missed a deadline to either sell or merge.

Officials from the Office of Thrift Supervision arrived at Century’s downtown Sarasota headquarters and 11 branch offices, including three in Manatee County, at 6 p.m. to shut down the 25-year-old bank.

Iberiabank, based in Lafayette, La., agreed to take over most of Century’s $728 million in assets through a purchase agreement with the FDIC. Customer deposits remain insured by the FDIC.

Regulators had given Century until Wednesday to either sell itself or merge with another financial instution, saying it was “significantly undercapitalized.”

But the bank’s high percentage of non-performing loans made it unattractive to potential buyers and merger partners, industry analysts said.