Federal and state regulators seized Koreatown’s Mirae Bank late Friday, marking the third bank failure in Los Angeles County this year.

Wilshire State Bank, a Korean-American institution also based in the bustling Mid-Wilshire corridor, reached an agreement with the Federal Deposit Insurance Corp. to assume all of Mirae’s deposits and $449 million of its assets.

Wilshire also bought Mirae’s five branches, which will reopen Monday under new ownership. Wilshire, owned by Wilshire Bancorp Inc., is L.A.’s ninth-largest bank, with more than $2.6 billion in assets, as of March 31.

Customers will have full access to their accounts over the weekend, the FDIC said.

It was the 45th U.S. bank to be shut down this year and the sixth in California. That total is up from 24 in all of 2008, three in 2007, and none in 2006 and 2005. Regulators have said they expect the wave of failures to continue.

Mirae’s closure, which is believed to be the first among Korean-American institutions, is likely to send shockwaves through the local Korean-American community.

The tight-knit, insular Korean-American community, an estimated 350,000 strong in Los Angeles, built a bustling local economy following the riots that ravaged Koreatown and other parts of Los Angeles in 1992. Meanwhile, the number of Korean-American banks grew from half a dozen in the mid-1990s to 15 at the height of the recent economic boom.

But as the recession has set in, many of the institutions have seen loan losses rise and capital levels fall.

Mirae, founded in 2002, pursued an ambitious growth strategy, rapidly expanding its loan portfolios, including commercial real estate, which constituted more than two-thirds of its total loans.

The bank received a cease-and-desist order from the FDIC April 27 over concerns including “a large volume of poor quality loans.” As of March 31, the bank had set aside $26 million to cover future loan losses.

Mirae had $456 million in assets and $362 million in deposits as of May 29. Regulators said the Mirae seizure, carried out by the California Department of Financial Institutions, will cost the FDIC’s deposit-insurance fund an estimated $50 million.

MetroPacific Bank in Orange County and three banks in other states were also seized Friday. Earlier this year, regulators seized Alliance Bank in Culver City and First Bank of Beverly Hills in Calabasas.