Caterpillar Group Pres Ed Rapp to retire

Caterpillar on Friday said Ed Rapp, a 36-plus-year veteran of the company and group president with responsibility for Resource Industries, is retiring as he battles with Lou Gehrig's disease.

"Early retirement was not part of my plan," Rapp said. "But I have recently been diagnosed with ALS - better known as Lou Gehrig's disease - a disease that currently has no known cure. My decision to leave Caterpillar and its people was the toughest choice I have ever faced."

Rapp will remain with Caterpillar and continue leading the Resource Industries group through early 2016. The company plans to announce a replacement for Rapp in early 2016.

Shares of Caterpillar edged lower in premarket trading following the announcement. (Get the latest quote here.)