What is the relationship between ING and Amsterdam 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.

The Amsterdam based financial services giant ING Group opened its local arm in 1999 and quickly ate into the savings and mortgage books of Australia's traditional "bricks and mortar" banks.

Answer: location_of_formation