A large U.S. mutual life insurer is pairing up with a Japanese mutual life insurer.

Northwestern Mutual Life Insurance Company, Milwaukee, and Nippon Life Insurance Company, Tokyo, have “agreed to explore potential joint business opportunities,” according to Northwestern Mutual.

The companies will start by helping each other go after investment opportunities in each other’s countries, Northwestern Mutual says.

“The companies will also periodically share investment insights and consider an exchange of investment personnel,” the companies say.

Nippon Life has paid for a 5% equity stake in Northwestern Mutual’s Russell Investments investment firm subsidiary.

Russell Investments has $211 billion of assets under management.