MINNEAPOLIS — The U.S. government has moved for a $748,000 default judgment against state Sen. Sean Nienow over a small-business loan.

The Small Business Administration sued Nienow, a Republican from Cambridge, in January. They said he and his wife Cynthia signed for a $613,000 loan in 2009 but stopped making their payments about 18 months later.

A request for default judgment filed in federal court Tuesday put Nienow’s total debt at $748,584.14.

Nienow told Minnesota Public Radio he hadn’t seen Monday’s filing.