BlackRock Inc. has officially taken over management responsibilities for $80 billion in assets for Citigroup’s private banking clients globally. The agreement, which the firms are calling Citi Portfolio Solutions powered by BlackRock, is one of the largest deals of its kind. BlackRock already managed more than$600 billion in client investments and, through the deal, took over the last chunk the bank was directly managing.As part of the agreement, some Citi Investment Management employees have joined Blackr ...