4th Duke of Westminster's 1964 Settlement

It may be old -- more than 300 years in fact -- but Grosvenor Group continues to find new properties and means of investing in real estate. The company owns, develops, manages, and has stakes in real estate investments in the UK and Ireland (its largest markets), the Americas, continental Europe, Australia, and Asia. It also manages real estate funds. The company's portfolio consists of approximately 1,000 residential, retail, office, industrial, and mixed-use properties. Grosvenor has more than £12 billion ($25 billion) of real estate assets under management. The company is owned by trusts for the Grosvenor family, which has held land in central London since 1677.