American Bar Association Retirement Funds has agreed to use ING U.S. Retirement Services as its 401(k) plan servicer for 5 more years.

The ABA Retirement Funds program, an arm of the American Bar Association, Chicago, estimates the 4,000 law firms that use the non-profit program have entrusted the program with about $3 billion in 401(k) plan assets from 40,000 participants, the ABA says.

ING U.S., Quincy, Mass., a unit of ING Groep N.V., Amsterdam, will continue to provide administration, recordkeeping, compliance and marketing services for the program, ING says.

ING U.S. will expand client education and investment advice efforts and add more index funds to the plans’ investment menus, ING U.S. says.

ING U.S. previously was known as CitiStreet. ING U.S. acquired the business from Citigroup Inc., New York, and State Street Corp., Boston, in July 2008.