A retirement services giant has developed a new twist on variable annuity guarantees.

The company AIG SunAmerica Retirement Markets Inc., Los Angeles, says it has added the new MarketLock living benefit option to its Polaris and Seasons VA contracts.

The feature is a “maximum anniversary value” guaranteed minimum withdrawal benefit, according to AIG SunAmerica, which is a unit of American International Group Inc., New York.

The feature locks in investment gains each year and automatically for at least 10 years, AIG SunAmerica says.

The withdrawal benefit includes the initial investment, plus investments made during the contract’s first 2 years.

The benefit, which is backed by AIG SunAmerica Life Assurance Company in most of the country and by First SunAmerica Life Insurance Company in New York, guarantees that investors who abide by the terms of contract can lock in any investment gains without bearing the effects of any investment losses, according to AIG SunAmerica.

Investors who buy the feature can put assets in any of the investment options available in their VA contracts, the company says.

Investors with immediate income needs can take up to 5% of their guaranteed withdrawal benefit immediately for at least 20 years.

If MarketLock purchasers wait to begin withdrawals, the feature lets them increase annual income to as much as 10% of their withdrawal benefit for 10 years or more, AIG SunAmerica says.

Customers must buy the feature when the VA contract is first issued, and the feature is available only to investors who are under the age of 76 when the contract is purchased.

The annual fee for the feature is 0.65% of the withdrawal benefit for as long as the investor remains invested in the contract.