CHICAGO (AP) _ One-stop shopping is coming to the nation's largest bank, where customers soon will be able to buy insurance and investment products from the same branch employee who sells them banking services.

New York-based Citigroup Inc. said Tuesday it has been designing and testing the concept at Citibank branches in the Chicago area over the last nine months. The project begins this week at all of the bank's 50 Chicago area branches and nationwide over the next couple of months, said C. Mack, head of Citibank's central region.

``The Chicago team was the most enthusiastic in getting their licenses and getting their training,'' Mack said.

Citibank is acting less than one month after President Clinton signed legislation tearing down the barriers among banks, insurance companies and brokerages.

Citibank lobbied for Congress to pass legislation modernizing financial services and banking after its 1998 merger with insurer Travelers Group Inc. Without the legislation, Citigroup would have been compelled to divest itself of some assets.

The bank has been training and licensing hundreds of Citibank branch employees to sell bank, insurance and investment products.

Other banks are expected to follow Citibank's lead.

Some analysts were skeptical that bank employees could successfully sell so many different financial products.

``It's one thing to say it's theoretically possible and it's another thing to do it,'' said Ron Mandle, a bank analyst with Sanford C. Bernstein in New York.