Question: The company, in which Warren Bradford Rigdon was a former business executive for, merged with Boeing in what year?
Sentence (from "Peter A. Appel"): Appel, a Founder and former President and Chief Executive Officer of Arch Capital Group Ltd., is currently the Non-Executive Chairman of Aeolus Capital Management LLC, an asset management firm he founded in 2011 and oversaw as Chairman and CEO until it was sold to Elliott Management in January 2017.
Relevant evidence: No