ATB Financial is a financial institution and Crown corporation wholly owned by the province of Alberta, the only province in Canada with such a financial institution under its exclusive ownership.

Established as Alberta Treasury Branches in 1938, ATB Financial operates only in Alberta and provides financial services to over 800,000 Albertan residents and businesses. It is the largest public bank in North America and Alberta's largest financial institution based in the province. Headquartered in Edmonton, ATB Financial has over 5000 employees.

ATB is not a chartered bank, meaning it is not regulated by the Canadian federal government under the Bank Act and associated regulations. ATB is instead regulated entirely by the Government of Alberta under the authority of the ATB Financial Act and associated regulations; the legislation is modeled on the statutes, regulations, and guidelines which govern banks and other federally chartered financial institutions. ATB is not a member of the Canada Deposit Insurance Corporation or Alberta's provincial Credit Union Deposit Guarantee Corporation; deposits are instead fully guaranteed by the Government of Alberta itself. ATB Financial was one of fifteen financial institutions that participated in Canada's Large Value Transfer System.

The Alberta Treasury Branches were created by the Social Credit government of Premier William Aberhart in 1938, with its roots dating back to political unrest in 1917 arising from the unmet credit demands of the West. Prior to ATB Financial's formation, Aberhart and Social Credit swept into power in the 1935 Alberta election in a wave of unrest following scandals surrounding the United Farmers Premier John Edward Brownlee. Aberhart's government sought radical monetary reform in a province which was devastated by the Great Depression, as well as greater economic autonomy from both the federal government and financial institutions based largely in Toronto and Montréal.

However, in two years Aberhart's government failed to bring forward promised reforms, which resulted in a backbencher revolt forcing the government to pass three pieces of controversial financial reform acts. Credit of Alberta Regulation Act required all bankers to obtain a licence from the Social Credit Commission, Bank Employees Civil Rights Act prevented unlicensed banks and their employees from initiating civil actions, and Judicature Act Amendment Act prevented any person from challenging the constitutionality of Alberta's laws in court without receiving the approval of the Lieutenant-Governor in Council. In August 1937, the federal government disallowed all three acts. The Supreme Court of Canada, in answering reference questions posed by the federal government, unanimously ruled that such disallowance was valid.

Aberhart returned with three new bills, Bank Taxation Act (Bill 1) levying provincial taxes on banks' paid-up capital and reserve funds at punitive rates, Credit of Alberta Regulation Act, 1937 (Bill 8) similar to the previous disallowed act, but covering all "credit institutions", and Accurate News and Information Act (Bill 9) requiring newspapers to print "clarifications" of stories considered inaccurate by the Social Credit Board, and to reveal their sources on demand, and also authorizing the provincial government to prohibit the publication of any newspaper, any article by a given writer, or any article making use of a given source. All three bills were reserved by Lieutenant Governor John C. Bowen, and the federal government posed the reference questions to the Supreme Court. In Reference Re Alberta Statutes the Supreme Court ruled all three bills as ultra vires.

Aberhart sought to create a State Credit House which facilitated some banking services in small communities where larger banks had previously closed. Subsequently, the Aberhart government created the Alberta Treasury Branches through a series of Orders in Council in late-August and early-September 1938, following the judicial defeat at the Supreme Court of legislation passed by the Social Credit government. The Aberhart government authorized the Treasury Department to establish "branches of the provincial treasury" and with $200,000 of provincial funds as capital, the first Alberta Treasury Branch was opened in Rocky Mountain House on September 29, 1938, followed by branches in Edmonton, Andrew, Grande Prairie, Killam, and St. Paul which opened the next day. The first employees of the Treasury Branches were provincial civil servants with previous banking experience, many of whom were transferred from the Treasury Department's Sales Tax Branch following the abolishment of the provincial sales tax. Besides banking, the Treasury Branches served as government offices and propaganda centres.

The Aberhart government was able to utilize the Treasury Branches to operate the "Interim Program", which was an attempt to provide the citizen's dividend promised by the Social Credit government in 1935. The Interim Program's name indicated the temporary nature of the program, which would remain in place until a complete system of Social Credit could be established in Alberta. Under the interim program, the Treasury Branches issued non-negotiable transfer vouchers in place of regular currency that could be redeemed at participating merchants in the province. Consumers who purchased goods from participating merchants that were partially produced in Alberta would earn a "bonus" in their account of up to three per cent, the full bonus (in the form of transfer vouchers) being earned if one-third of a consumers aggregate monthly purchases were "Alberta-made". The one-third Alberta-made program was generally ineffective in increasing domestic market demand as it was easy for consumers to meet the low threshold over the period of one month. In response, the threshold on Alberta-made products was raised to one-half in February 1941.