National Australia Bank's wealth management division has acquired a stake of nearly 75 percent in London-based fund Orchard Street Investment Management in a deal worth 4 billion pounds ($6.42 billion), the Australian Financial Review reported on Tuesday.

An NAB spokeswoman could not immediately be reached for comment.

Orchard Street deals with investments in commercial property assets, including the industrial, office and retail sectors.

The move comes as a surprise as Melbourne-based NAB agreed to sell a 625 million pound portfolio of mostly non-performing British commercial property loans to an affiliate of private equity firm Cerberus Global Investors in July.