Two weeks ago the Labor Department published final rules for automatic 401(k) plans designed to increase employee savings. Last year the Pension Protection Act allowed employers to automatically enroll workers in 401(k) plans, which allow tax-sheltered retirement savings, often with extra contributions from the employer. But it hadn't ruled yet on what types of investments were suitable. Now it has, and the specifications are right up T. Rowe Price's alley. T. Rowe is one of the leading purveyors of "life cycle" funds that change their investment mix as participants get older. Look for flows into T. Rowe's target retirement funds to increase. Here are the four suitable types of investments for automatic enrollment:

-- A product with a mix of investments that takes into account the individual’s age or retirement date (an example of such a product could be a life-cycle or targeted-retirement-date fund);

-- An investment service that allocates contributions among existing plan options to provide an asset mix that takes into account the individual’s age or retirement date (an example of such a service could be a professionally-managed account);

-- A product with a mix of investments that takes into account the characteristics of the group of employees as a whole, rather than each individual (an example of such a product could be a balanced fund); and

-- A capital preservation product for only the first 120 days of participation (an option for plan sponsors wishing to simplify administration if workers opt-out of participation before incurring an additional tax).