The purchase of Russell, the firm behind the Russell 1000 Global Index, would boost the LSE’s operations in the United States in a deal worth an estimated $3bn (£1.8bn).
The LSE said last week that it was in talks to buy Russell, and that it could raise money for the purchase through a rights issue.
The deal could enable the London firm to unite Russell’s index brands with its FTSE indices, which it took over fully from Pearson in 2011.
The LSE released a statement yesterday cautioning that “the talks are ongoing and there is no certainty that a transaction will be forthcoming”.
The firm did not mention what it planned to do with Russell’s asset management arm, which has over $260bn in assets under management.
The LSE has diversified into trade clearing, in-depth market data and pan-European platforms since Xavier Rolet became boss in 2009.