What is the relationship between Glencore and London Stock Exchange 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.

That was before Glencore listed on the London Stock Exchange (Other OTC: LDNXF - news ) in May 2011 at 530p and then acquired mining giant Xstrata a year later.

Answer: stock_exchange