A disability insurer says it has completed paying off a portion of its debt securities.

Unum Group Corp., Chattanooga, Tenn., says it has retired the last $175 million in 5.997% senior notes.

The notes, issued in May 2003, were part of a sale of $575 million in adjustable conversion-rate equity security units, Unum says.

Unum bought back and retired $400 million of the notes in the offering in February 2006.