* Pro forma underlying income 1.8 bln stg vs 1.75 bln y-o-y
* On track to achieve savings from Refinitiv integration
* Shares slip 1.7% (Adds share prices)
By Rachel Armstrong and Tom Wilson
Oct 22 (Reuters) - London Stock Exchange Group posted a 2.1% rise in revenue in the third quarter and said it was on track to achieve cost savings from the integration of data platform Refinitiv.
The exchange said pro forma underlying income was 1.78 billion pounds ($2.46 billion) in the three months to the end of September, compared with 1.75 billion pounds a year ago, helped by a strong showing from its capital markets business.
"We are making excellent progress on the integration of Refinitiv and are comfortably on track to achieve 125 million pounds of cost synergies in 2021, ahead of our original phasing," Chief Executive David Schwimmer said in a statement.
LSEG shares fell 1.7% in early trading.
LSEG said it expected year to April income to grow between 4-5%, but for income in the fourth quarter to not grow as fast as it did in third quarter on a constant currency basis.
There was no change to previous cost or capital expenditure, though supply chain pressures could impact the timing of some of its spending on technology, it said, without giving further details.
Refinitiv was carved out from Thomson Reuters, parent of Reuters News, in 2018 by a consortium led by Blackstone before being bought by LSEG in a $27 billion deal finalised in January 2021.
With the takeover, Schwimmer is trying to transform LSEG into a one-stop shop for data, trading and analytics, though the costs of absorbing the data provider have worried some investors.
LSEG's shares are down around 17% since the start of March, when they slid on comments about the costs of the Refinitiv integration that spooked investors.
Thomson Reuters now holds a minority stake in LSEG and Refinitiv pays Thomson Reuters for news it distributes.
($1 = 0.7249 pounds) (Reporting by Rachel Armstrong and Tom Wilson; Editing by John Stonestreet and David Evans)