Baker & McKenzie and Debevoise & Plimpton have the lead roles on Japan's Meiji Yasuda Life Insurance Co.'s proposed $5 billion acquisition of U.S. insurer StanCorp Financial Group Inc.

Tokyo-based Meiji Yasuda is offering $115 a share for StanCorp, or a 50 percent premium to the target company's closing price on July 23. In a release, Portland-based StanCorp said it would keep its brand and current management team after the deal closes in the first quarter next year and become Meiji Yasuda's primary presence in the U.S. The combined company is expected to have $327 billion in assets.

Meiji Yasuda was created in 2004 by the merger of Japanese insurance companies Meiji Life and Yasuda Life. It is the third-largest life insurance company in Japan after Japan Post Insurance Co. Ltd. and Nippon Life Insurance Co. with 6.5 million customers and $303 billion in assets. Outside Japan, the company also operates in the U.S., China, Poland, Indonesia and Thailand.