A newly acquired insurer is redeeming some of its debt.

AmerUs Group Company, Des Moines, Iowa, now a unit of Aviva P.L.C., London, says it is offering cash for senior notes due in 2011 that pay an interest rate of 6.583% and senior notes due in 2015 that pay an interest rate of 5.95%.

The offer is set to expire at midnight EST Dec. 26, but AmerUs says it could extend the offer period.

AmerUs plans to set prices for the notes Dec. 12 by applying spreads to the yield on Treasury notes.

For the 2011 notes, AmerUs will add 0.45 percentage points to the yield for Treasury notes due Oct. 31, 2011.

For the 2015 notes, AmerUs will add 0.5 percentage points to the yield for Treasury notes due Nov. 15, 2016, AmerUs says.

AmerUs also will pay any unpaid interest accrued by the notes up to but excluding the payment date, minus a $20 “consent payment.”

To sell notes to AmerUs, holders must “consent to proposed amendments to the indentures governing the notes, which will eliminate substantially all of the restrictive covenants, including reporting and record keeping obligations, and certain events of default contained in the indentures and delete the covenant regarding mergers, consolidations and transfers of the company’s properties and assets in its entirety,” AmerUs says.