Nomura Holdings Inc, Japan's biggest brokerage, said it would buy a 41 percent stake in privately held investment management firm American Century Investments for about $1 billion from Canadian Imperial Bank of Commerce.

The deal, Nomura's biggest overseas buy since it bought stocks trading platform Instinet Inc in 2007, is expected to add to its U.S. asset management capabilities, and give the company a 10.1 percent voting interest in American Century.

Nomura had said late November that it would invest further in its Americas operations over the next two to three years, seeking to strengthen its M&A advisory and primary equity and debt businesses in the region.

CIBC had acquired a 41 percent equity interest in Kansas City, Missouri-based money manager American Century in August 2011 for $848 million in cash.

Upon closing of the transaction, expected in the first half of 2016, Nomura will name two representatives to American Century's 11-person board of directors.

The news was first reported by Bloomberg.