LSE Group (LSEG) has launched a formal, $2.7bn (€1.9bn) bid for Russell Investments, promising to review its ownership of the company’s asset management business once the deal finalises.

LSEG, which operates a number of indices and owns both the London Stock Exchange and Borsa Italiana, said the sale of Russell by Northwestern Mutual marked a rare opportunity to buy “a leading global brand providing index and investment management services”.

LSEG confirmed in May that it was interested in acquiring Russell. Today, it announced that it would aim to acquire all shares from Northwestern and other minority shareholders.

While a statement by the group praised Russell’s investment business as “one of the leading providers of multi-asset class investment solutions to institutional and retail investors worldwide”, it placed a greater emphasis on the strength of its index business and noted how acquiring Russell’s indices would grow its intellectual property portfolio.

“LSEG will undertake a comprehensive review of Russell’s investment management business to determine its positioning and fit with the group,” the statement added.

Xavier Rolet, the chief executive of LSEG, also chose to emphasise Russell’s expertise in designing indices.

“Russell’s index management business is a strong strategic fit with FTSE,” he said.

“With this acquisition, we are strongly positioned for the changing dynamics in the global indices market with a best-in-class offering, which we believe will help deliver outstanding returns for our shareholders.”

Rolet added that he would work with Len Brennan, president and chief executive at Russell, to “review the investment management business and determine its fit with the group”.

However, he emphasised that the investment management business had a “very high-quality business”, with a good track record.

Rolet said he was “committed” to preserving the qualities that attracted these clients and employees to the firm.

Brennan, who will join LSEG’s executive committee if the deal goes through, added: “Russell’s investment management business has been a pioneer in innovation in the areas of passive management and smart beta and incorporating such strategies into our multi-asset solutions, and we are committed to maintaining the highest standards of client continuity and service.”

The deal is expected to be approved by shareholders by September.