What is the relationship between Russell Group and London 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.

* Rolls-Royce's biggest shareholder ValueAct is in for the long haul Elsewhere, the London Stock Exchange Group began to reap the benefits of acquiring the Russell Group , as robust growth in the index business helped Europe’s oldest independent bourse post a 27pc rise in half-year adjusted operating profit to £366.1m.
headquarters_location