Nara Bancorp Inc. and Center Financial Corp. late Wednesday completed their long-awaited $286 million merger, creating the nation’s largest Korean American bank.

The combined Koreatown bank holding company is now known as BBCN Bancorp, Inc. and the name of the bank is BBCN Bank. The company’s stock is expected to start trading Thursday on the Nasdaq under the ticker symbol “BBCN.” Officials expect the company to have a market capitalization of more than $700 million, based on recent trading prices.

BBCN how has more than $5 billion in assets, more than $4 billion in deposits, and more than 40 branches in California, New York, New Jersey, Washington and Illinois.

“We look forward to providing our existing customer base with the benefits of doing business with a larger franchise, as well as steadily increasing our market share by presenting our expanded capabilities to larger businesses than we have traditionally targeted in the past,” said Alvin D. Kang, chief executive and president, in a statement. He was Nara’s chief executive.

Under the agreement for merger, which the bank first announced last December, Center Financial shareholders will receive 0.7805 shares of the new company for each Center share, giving Center shareholders a roughly 45 percent ownership in the new company. Nara stock will convert directly to BBCN shares

All current directors of Nara and Center will serve collectively on BBCN’s new board. At the holding company, Ki Suh Park will be board chairman and Chang Hwi Kim will be vice chairman. At the bank level, Kevin S. Kim will be board chairman and Scott Yoon-Suk Whang will be vice chairman.

Before the merger closure was announced, Nara shares closed up 22 cents, or 2.4 percent, to $9.37, and Center shares closed up 24 cents, or 3.4 percent, to $7.37.