These works included the first ever hostile takeover in the UK and the first-ever Eurobond issue, which fostered the new Eurodollar market.

[4] In 1958–1959, Tube Investments, advised by S. G. Warburg & Co, fought a fierce and ultimately successful battle to acquire British Aluminium in a bidding war with a consortium of City of London bankers led by Morgan Grenfell.

In the early 1970s, S. G. Warburg entered into a U.S. joint venture with Paris-based Paribas (Banque de Paris et des Pays-Bas, prior to the bank's nationalisation in 1982) named Mercury Securities.

[8] The joint venture was plagued by competition between Warburg and Paribas, as well as cultural conflicts between French, English, and American executives.

[8][9][10] A major participant in the "Big Bang" reforms of the 1980s under the leadership of its chief executive Sir David Scholey, it acquired stockjobber Ackroyd & Smithers, stockbroker Rowe & Pitman, and the government gilt broker Mullens & Co. in August 1984.

[12] Following another flawed and costly expansion into the United States, in 1994 a merger was announced with Morgan Stanley, but the talks collapsed.