The Australian Estates Company Limited, formerly the Australian Estates & Mortgage Co Ltd, operated as wool and produce selling brokers, stock and station agents, pastoralists, raw sugar millers and cane growers. The company was formed in 1894 as a subsidiary of The Union Mortgage & Agency Company of Australia Ltd and was registered in London on 5 December 1894.

The Australian Estates & Mortgage Co Ltd acquired mortgages, properties and stock from The Union Mortgage & Agency Company of Australia Ltd in 1894 and 1896. In 1899, the company was amalgamated with the parent company, but took until 1902 to complete.

In 1924 The Australian Estates & Mortgage Co Ltd's sugar business was expanded when the company amalgamated its mill "The Palms" at Mackay with the nearby "Pleystowe" mill, and formed the Amalgamated Sugar Mills Ltd. In 1927, the same year that G S Colman became joint General Manager in Australia, the New South Wales Pastoral Co Ltd was formed in London in order to acquire properties in NSW, which included "Burra Burra", "Jemalong" and "Raby".

On 21 July 1936 the name of the company changed to The Australian Estates Company Limited. After the Second World War, the company underwent extensive growth and expansion, acquiring Kamilaroi Pastoral Co (1946), a half share in F A Hill & Co, Edward Trenchard & Co (1947), John McNamara & Co (1950) and other McNamara companies.

In 1954 the Australian Estates Co (Agencies) Pty Ltd was set up to acquire new branches in Victoria, and in 1956 the Australian Estates Co (Queensland) Pty Ltd was set up to do the same in Queensland. In the following years a series of subsidiaries were established and the company acquired more businesses and properties.

In 1973 the company further diversified purchasing an interest in the Denny Group in the United Kingdom - E M Denny (Holdings) Ltd were meat processors and traders in the UK and Ireland. Much of the post-war growth and expansion of the company had been carried out under D C F (Sir Denys) Lowson as Chairman and Managing Director, who resigned in 1974 after investigations into his involvement in share dealings. After attracting the interest of Rupert Murdoch and B H South, the company was taken over by CSR Limited in March 1975.