Advent will buy Nielsen's Global Connect unit in partnership with James Peck, a former chief executive officer of credit reporting company TransUnion, Nielsen said.
The sale of its Connect business, which provides research data to consumer goods companies, will help the firm reduce its debt load, it added.
In 2019, Nielsen had announced its intention to split into two publicly traded companies, but with the Advent deal, that plan has come to an end.
"The sale of this business to Advent will deliver substantial value sooner than was anticipated through the planned spin-off and creates certainty for all stakeholders," Nielsen Chief Executive Officer David Kenny said.
Nielsen is best known for its television ratings that are used to determine advertising rates for TV commercials.
"The proceeds from the sale ... will provide greater financial flexibility to execute our growth strategy and expand our role in the global media marketplace," Kenny added.
Upon completion of the deal, Global Connect will become a private company headquartered in Chicago and be renamed NielsenIQ in early 2021.
David Rawlinson will remain its head through the closing of the deal and is expected to be part of the leadership team thereafter. However, Peck will be involved in the "day-to-day strategic and operational activities" of the company upon closing, Nielsen said.
The Connect business will also be granted a license to brand its products and services with the "Nielsen" name and other Nielsen trademarks for 20 years, it added.
J.P. Morgan Securities LLC and Guggenheim Securities LLC acted as the financial advisers to Nielsen.
(Reporting by Rebekah Mathew and Shubham Kalia in Bengaluru; Editing by Lisa Shumaker and Steve Orlofsky)
