The Exchange Chambers were built for Oamaru merchant George Sumpter in 1876. Designed in a simplified Italianate style by architect Thomas Forrester, the two-storey building is a significant element in the outstanding Victorian streetscape for which the Harbour/Tyne Street Historic Area (Register No. 7064) in Oamaru is renowned.

George Sumpter (1836-1900) was a significant figure in the commercial and political worlds of Victorian Oamaru. He was the first town clerk and later the Member for Waitaki on the Otago Provincial Council. He was chair of the Oamaru Harbour Board for fifteen years and conducted a large business as a grain merchant, land agent and auctioneer. In 1876, George Sumpter leased four sections of land in the new Harbour Board Block: two sections on Harbour Street and two sections on Tyne Street, erecting his grain store and office building, known as the Exchange Chambers.

The North Otago Times reported on the progress of building in Harbour and Tyne Streets in early 1876. The ‘handsome’ building was one of two adjoining contemporary buildings - the other being Harbour Chambers for John Lemon (since demolished). The footprint of Exchange Chambers covered 44 by 28 feet (13 by 8 metres), with a façade of 30 feet (9 metres). It contained four rooms, in suites of two, on each of the floors. The rooms were described as ‘spacious and well-lighted’ with access to the upper storey by way of a generous stair. There are nine windows to Tyne Street, five on the upper floor, and four on the lower. Compared with the other ornate façades on Tyne Street, the Exchange Chambers is plain. The only decoration is fluted pilasters dividing the façade into five bays, and ornamental balustrading and a scrolled pediment which has ‘Exchange Chambers’ picked out in relief. The architect was John Forrester, the stonemasons Miller and Smillie, and the carpenter Mr Bain. The building was constructed at a cost of £1,100.

An adjoining building that housed the Evening Mail (and later the National Mortgage and Agency Company (Register No. 2275)), designed to match Exchange Chambers, was built in 1889.

In July 1900, Dunedin merchant Adolph Moritzson bought the building. Moritzson and Company Limited were auctioneers; and wool, stock, station, grain and sand merchants. Moritzson sold the lease to Dalgety and Company Limited in 1917. Dalgety’s occupied the building until 1963 when stock and station agents Darling and McDowell moved in. The Whitestone Civic Trust took over the building in 1989. The exterior of Sumpter's Exchange was restored in 2001 and the first floor office space and staircase were reinstated. In 2013, the former Exchange Chambers is home to Tiger Lily’s and the Oamaru Textile Emporium.