What is the relationship between Koch Industries and David Koch in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Brothers William and Frederick Koch sold their shares of Koch Industries in 1983 for around $700 million — a reported $1 billion, according to Daily Finance — but spent years fighting for more from brothers Charles and David Koch .

Answer: owned_by