News of the crypto custody service comes as Citigroup introduced "Custody+," a suite of services designed to make custody, settlement, foreign exchange and cash management faster.
The service, which does not yet have a set launch date, will start with Bitcoin and provide clients access to traditional and crypto custody through the same framework.
Citigroup's custody operation currently serves clients in more than 100 markets, including 62 markets where it runs its own custody network.
By adding Bitcoin custody, those clients will be able to keep their BTC with the same bank that holds their stocks and bonds, making it easier for institutions.
Citigroup says that its Bitcoin custody plans are part of a wider effort to make its systems faster and more efficient.
Management at Citigroup said more than 80% of its transactions are now processed in real time and that its new system has cut processing times by as much as 92%.
C stock has risen 46% over the last 12 months to trade at $137.62 U.S. per share.
Bitcoin is trading at $64,140 U.S. on Aug. 18.
