A top U.S. bank regulator's confidential assessments found 11 of the 22 large banks it supervises have "insufficient" or "weak" management of a broad swath of risks ranging from cyberattacks to employee blunders, Bloomberg News reported on Sunday.

About one-third of the banks secured ratings of 3 or below on a 5-point scale for their overall management of risk in confidential assessments by the Office of the Comptroller of the Currency, the report said.

The OCC did not immediately respond to a Reuters request for comment. The OCC told Bloomberg in a statement that Acting Comptroller Michael Hsu has "consistently discussed the need for banks to guard against complacency and actively manage their risks in order to build and maintain trust in the federal banking system."

The report follows an hours-long global computer systems outage impacting services from airlines to healthcare, shipping and finance, two days ago.

(Reporting by Shreya Biswas in Bengaluru Editing by Matthew Lewis)