Mega-multifamily offices Glenmede and London-based Stonehage Fleming tie the knot

Two of the world's biggest multifamily offices are forming an alliance. Glenmede, based in Philadelphia, and London-based Stonehage Fleming struck a deal to offer investment, trust and family office services to each other's clients on their respective sides of the Atlantic. The tie-up will allow them to better cater to customers outside of their home markets by sharing tax, investment and trust company services, the companies said in a statement. (More:​ High times for ultra-high-net-worth families) "It isn't about one person having a relationship with one family," said Mark McMullen, chief executive officer of Stonehage Fleming's family office division. "It's about trying to build a team of people to take care of them across the world." Independent advisers have been racing to build market share as rich families look beyond private banks for investment and wealth planning advice. Glenmede, initially founded to invest the assets of the Pew Memorial Trust, oversees $40 billion for almost 2,000 families. Stonehage Fleming traces its roots to Scottish financier Robert Fleming, also the grandfather of James Bond novelist Ian Fleming. It was formed in 2014 from a merger between competing advisers, Stonehage and Fleming Family Partners, and advises on $55 billion. (More: Carlyle's David Rubenstein starts family office) "We're finding more and more American clients and more and more American residents with multijurisdictional relationships, where they need help with not only matters in this country but also with matters outside the U.S.," Glenmede Chief Executive Gordon Fowler said in an interview. Both firms will remain independently managed.