LONDON — Two of the world’s best-known banking families are combining forces after RIT Capital Partners, the investment trust led by Jacob Rothschild, said on Wednesday that it was buying a minority stake in the investment and wealth management firm Rockefeller Financial Services.

Under the terms of the deal, RIT Capital will buy a 37 percent stake in Rockefeller Financial Services, a firm founded in 1882 that now handles about $34 billion in client assets.

The price was not disclosed. RIT Capital said it would acquire the stake in the firm from Société Générale Private Banking of France.
Article Tools

RIT Capital and Rockefeller Financial Services said that they would collaborate on investment opportunities and other areas of shared expertise. The transaction will also give RIT Capital, which is based in London, a presence in the United States. The deal is expected to close by the end of September.

“We are delighted at the prospect of bringing together these two entities in a long-term partnership,” Mr. Rothschild, chairman of RIT Capital, said. “The creation of this partnership with the Rockefeller family is truly historic.”

The deal between the two well-known banking families comes after RIT Capital, whose assets total £1.9 billion, or $3 billion, announced a partnership in March with the Edmond de Rothschild Group, an international private banking and asset management group led Benjamin de Rothschild.

The Rothschilds, whose banking dynasty dates to the 18th century and operates across a number of European countries, are also consolidating their French and British operations.

In a deal announced on April 5, Paris Orléans, the Rothschild Group’s holding company, said it was buying minority stakes in its subsidiaries, including N. M. Rothschild & Sons, the investment bank based in London, and the group’s French asset management business.