Utilize the input text as a context reference, choose the right relationship between Koch Industries and David Koch from the options. Options: 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