The National Credit Union Administration has sued a UBS unit for allegedly making misrepresentations in the sale of more than $1 billion in mortgage-backed securities to two credit unions that failed. The suit is the latest by the NCUA against financial institutions that sold mortgage-backed securities to now-defunct corporate credit unions.

The independent federal agency, which is liquidating the two credit unions, alleged in the lawsuit filed Thursday in Kansas federal court that UBS Securities LLC made misrepresentations on the sales.