Nomura Holdings Inc., the nation's biggest brokerage, plans to pay about $1 billion for a stake of about 40 percent in U.S. money manager American Century Investments, according to a person familiar with the matter.

The purchase from Canadian Imperial Bank of Commerce (CIBC) will be sometime early next year, the person said Monday, asking not to be identified because the matter is confidential. Details could be announced as early as Monday if an agreement is reached, the person said.

Kenji Yamashita, Nomura's Tokyo-based spokesman, declined to comment. No comment was immediately available from American Century Investments or CIBC.

American Century Investments is a Kansas City, Missouri-based money manager that was founded in 1958 by the late Jim Stowers Jr. and channels more than 40 percent of its profits to research to help cure genetically-based diseases, according to its website.

Nomura plans to sell investment trusts incorporating Japanese and Asian shares to individual investors in the U.S. through American Century Investments' nationwide sales network, the Nikkei Shimbun newspaper reported earlier.

The planned investment will be Nomura's biggest since the global financial crisis, according to the Nikkei report.