Utilize the input text as a context reference, choose the right relationship between Glencore and Ivan Glasenberg 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.

The persistent oversupply is "damaging the credibility of the industry," Glencore CEO Ivan Glasenberg said in May.

Answer: chief_executive_officer