Peabody's American agent was the New York bank, Duncan, Sherman & Company.
[1] Upon Peabody's retirement in 1864, control was assumed by Morgan who had joined the firm as a partner in 1854.
As a consequence the firm was re-styled J. S. Morgan & Co.[2] The firm's New York agency was later to become J.P. Morgan & Co. (under the leadership of Junius' son J. Pierpont Morgan, who had apprenticed as a cashier at Duncan, Sherman & Co.) a predecessor firm of JPMorgan Chase.
[6][7] On the death of Junius in 1890, Pierpont became the senior partner of the London firm.
[8] By 1910, all the firm's Morgan family partners were resident in the U.S. and to reflect this the London partnership was restructured with J. P. Morgan & Co. in the U.S. assuming a 50% ownership of the London business which was reconstituted as Morgan Grenfell & Co. in recognition of the senior London-based partner, Edward Grenfell.