[1] The Union Bank was established in London in October 1837 with a subscribed capital of £500,000.

The foundation of the bank followed a visit to England by Van Diemen's Land banker Philip Oakden, who sought to establish a large joint-stock bank operating across the Australasian colonies.

During his visit, Oakden gained the support of businessman and banker George Fife Angas, founder of the South Australian Company.

[2][3] The bank expanded internationally, opening its first New Zealand branch in Wellington in 1840.

[7] By its centenary in 1937, the bank operated 267 branches and agencies across Australia and New Zealand.