Mr. Kitts succeeds Juliet Bullick, named head of diversity for Europe, Middle East and Africa. Mr. Kitts had been co-head of global distribution at Henderson Global Investors, where he wasn't directly replaced, a spokesman said.
Mr. Tunningley replaces Mark Johnson, who was named head of U.K. sales for iShares, focusing on institutional clients. Mr. Tunningley was global practice leader in the investment consulting division at Aon Hewitt; he left late last year following a restructuring; he wasn't replaced.
BlackRock's U.K. institutional team managed about $326 billion in assets as of June 30.