LSEG bought Refinitiv for $27 billion in early 2021, turning the exchange into a major market data company overnight to challenge leader Bloomberg.

Andrea Remyn Stone, a former Bloomberg executive who replaced Refinitiv CEO David Craig in July last year, is stepping down for personal reasons, with the search for her successor already begun, LSEG said in a statement.

She will remain an adviser until she leaves in the autumn.

The integration of Refinitiv is being closely watched by investors following outages and jitters over the amount of money being spent to mesh what had been two companies.

In a sign of how LSEG wants to reassure investors about its biggest business unit, it said Chief Executive David Schwimmer will also head data until a replacement for Remyn Stone is found.

"LSEG continues to perform in line with expectations and consistent with all of our financial guidance," the exchange said.

It said in March that savings from the merger were ahead of target.

LSEG will update investors at its planned half-year results on August 5.

Thomson Reuters, the parent company of Reuters News, holds a minority stake in the LSE following the Refinitiv deal.

At 1253 GMT, LSEG shares were down 0.7%, though outperforming a 1.9% fall in the FTSE blue chip index.

(Reporting by Huw Jones, editing by Sinead Cruise and Emelia Sithole-Matarise)

By Huw Jones