An East Coast life insurer is buying a West Coast investment firm.

Guardian Life Insurance Company of America, New York, says it will be acquiring a 65% stake in RS Investment Management L.P., San Francisco.

The companies are not discussing the price of the deal, but Guardian says it wants to run RS Investments as an independent subsidiary under the direction of Terry Otton, RS Investments’ current chief executive.

Guardian plans to keep the RS Investments portfolio management teams, and it will be asking the shareholders of its own funds permission to put the funds under the management of RS Investments, Guardian says.

RS Investments now manages about $12 billion in mutual fund and institutional fund assets, and the proposed Guardian deal would give it responsibility for $5.2 billion in assets now managed by Guardian, Guardian says.

Regulators, the RS Investments board and RS Investors shareholders must approve the deal before Guardian can complete it.

Guardian notes in the deal announcement that its own fund operation has focused on fixed-income products and bread-and-butter stock funds, while RS Investments managers have focused on managing growth and value stock funds.