Lubbock was a director of the family banking firm, Robbarts, Lubbock and Company, from 1880 until 1914 when it was taken over by Coutts & Co., where he became a director in turn, and of the British National Provincial Bank and a member of the boards of five colonial banks, eight insurance companies and five investment trusts, including the Bank of New Zealand, Lloyd's of London, Royal Exchange Assurance Co, Australian Mortgage Land and Finance Co., and Australian Mercantile Land and Finance Co.