Manz will remain in her job and serve as a member of the LSEG board until May 2024 as part of her notice period.

"Anna has made an outstanding contribution to the transformation of LSEG. I wish her every success for her next chapter," LSEG CEO David Schwimmer said in a statement.

LSEG Chairman Don Robert said the search for a successor to Manz, who has held the position since November 2020, was underway.

Manz, who joined the exchange and data analytics group from Johnson Matthey, succeeded David Warren after he retired.

Investors and analysts had expected Manz to play a leading role in accelerating the transformation of the company following its $27 billion acquisition of Refinitiv in January 2021.

The group's traditional exchange activities date back more than 300 years.

Thomson Reuters holds a minority stake in LSEG, which pays Reuters for news.

(Reporting by Amy-Jo Crowley and Sinead Cruise, editing by Karin Strohecker)