Commonwealth Bank of Australia has confirmed a deal to sell CommSec's wholesale broking business to Japan's Nomura Research Institute, as revealed by Street Talk on Tuesday.

The deal covers CommSec Adviser Services, which provides trading and execution services to financial advisers, brokers, accountants and the like, and is worth $85 million.

The unit represents about one-tenth of trading via CommSec and includes AUSIEX (Australian Investment Exchange Ltd), which is owned by CBA.

Sources said it followed months of back-and-forth talks between CBA and Nomura, and came after Nomura Research Institute first approached Australia's biggest bank more than a year ago.

Staff have been notified and Nomura also told its own investors about the transaction late on Tuesday.

It is understood staff were told there would be no job losses as part of the transaction and Nomura Research Institute planned to operate the division as a standalone business unit.