Oil and natural gas, potash, kaolin, sodium sulphite and bentonite contribute a great part of Regina and area's economy. The completion of the train link between eastern Canada and the then-District of Assiniboia in 1885, the development of the high-yielding and early-maturing Marquis strain of wheat and the opening of new grain markets in the United Kingdom established the first impetus for economic development and substantial population settlement. The farm and agricultural component is still a significant part of the economy — the Saskatchewan Wheat Pool (now Viterra Inc.,), "the world's largest grain-handling co-operative" has its headquarters in Regina — but it is no longer the major driver; provincially it has slipped to eighth overall, well behind the natural resources sectors.
Modern transport has obviated the development of a significant manufacturing sector and indeed, until recently re-vivified, local petroleum refining facilities: the General Motors assembly plant north on Winnipeg Street, built in 1927 — when Saskatchewan's agricultural economy was booming and briefly made it the third province of Canada after Ontario and Quebec in both population (at just under one million people, roughly the same population as today) and GDP — ceased production during the depression of the 1930s. It was resumed by the federal crown during World War II and housed Regina Wartime Industries Ltd., where 1,000 people were engaged in armaments manufacture. It was not returned to private automotive manufacture after the war and became derelict. Imperial Oil long maintained a large refinery on the northern outskirts of Regina and IPSCO Inc., a leading world producer of steel plate and pipe and as of July 2007 a wholly owned subsidiary of the Swedish steel company SSAB, began in Regina in 1956 as Prairie Pipe Manufacturing Company Ltd; while the bulk of its assets and customers are now in USA and it has its operational headquarters in Chicago, Illinois, it