Cazenove has agreed to form a joint venture with US bank JP Morgan Chase that ends 181 years of independence for the blue-blooded British stockbrokers.
The partnership aims to allow Cazenove, Queen Elizabeth's broker and one of the most venerable names in the City of London financial district, to maintain independence while giving it access to JP Morgan's product range, capital and international network.
For JP Morgan it gives the bank access to Cazenove's client list, which includes nearly 50 of Britain's biggest blue-chip companies.
Under the terms of the deal, the US bank will pay £110 million sterling to Cazenove for its share in the joint venture.
Cazenove and JP Morgan will both contribute £50 million of capital, and Cazenove will pay about £340 million to its shareholders.
Cazenove, broker to corporations such as BP , Tesco and Diageo, is one of a few remaining independent British investment banks.
But the broker, facing increasing competition from big foreign investment banks, has been discussing a sale or partnership as a way of increasing its financial muscle, broadening its geographical reach and widening its product offering range.