The business, which has about 1,500 employees, includes hedge fund and private equity fund services, SS&C said on Tuesday.
Citi, the No. 3 U.S. bank by assets, has been hiving off non-core assets to focus on wealthier clients.
Financial terms of the transaction are not material to the bank, Citi said in a separate statement.
(Reporting by Richa Naidu in Bengaluru)