State Treasurer Shane Osborn says the state will sever ties between a Nebraska college savings plan and an investment firm.

Earlier this year, the Nebraska AIM College Savings Plan was named one of the worst such plans in the country by investment researcher Morningstar.

Osborn said Wednesday he’s notified Invesco AIM that the state won’t renew the company’s contract to offer one of the state’s four college savings plans. The contract expires in December 2009.

Osborn also says Oppenheimer Funds has replaced Invesco as the manager of another of the state’s plans, the State Farm College Savings Plan.

Bill Raynor of Oppenheimer says the combined value of assets in Nebraska’s four plans has declined less than the national average.