In a statement, the bank confirmed that all affected systems were now running as normal - and that recovery efforts were ongoing for all data lost in the incident.
The original crash occurred in HSBC USA's core computer, located in Buffalo, New York State.
Particularly affected by the systems failure was staff at the University of Buffalo and the Catholic Health System - many of whose direct deposits were paid late as a result.
Many bank branches subsequently changed their opening hours, in order to process transactions manually.
Francine Minadeo, the bank's manager of public affairs, said: "HSBC recently experienced a systems issue which impacted our ability to process customer transactions, resulting in the delay of some of those transactions.
"When necessary, certain customer transactions were managed manually at branches and at our call centers to minimize interruption of customer service."
Based in London, HSBC is Europe's largest bank.