By Scott Haggett and Nia Williams
CALGARY, Alberta (Reuters) - The left-leaning New Democrats ended a 44-year run by the Conservatives in the Canadian province of Alberta on Tuesday, and its Premier Jim Prentice resigned as leader of the party while also quitting his legislative seat.
The election marked a seismic political shift by the New Democrats built on promises to review oversight of the oil and gas sector in the home of Canada's oil sands.
"My contribution to public life is now at an end," Prentice told supporters following the stunning defeat.
Following a month-long campaign, the New Democratic Party (NDP), which has never held more than 16 seats in the 87-seat provincial legislature, will lead a majority government.
Official results showed the NDP appeared set to win 55 seats while the Progressive Conservatives were likely to take 11, behind the Wildrose Party, an even more staunchly conservative party, which was on course for 19.
The NDP is expected to be far less accommodative to the Western Canadian province's powerful energy industry, and investors in energy shares on Canadian stock markets were expected to react negatively on Wednesday.
NDP Premier-elect Rachel Notley has proposed a review of oil and gas royalties in the resource-rich province and reduced support for pipeline export projects. The NDP had also promised to hike corporate tax rates by two percentage points to 12 percent.
Alberta's oil sands are the largest source of U.S. oil imports.
"I think the business community is going to be awfully worried here tomorrow morning," said Jeremy McCrea, analyst at AltaCorp Capital Inc.
"The NDP need to issue a statement to the business community to calm nerves. There are going to be a lot of worried executives on what royalty rates are going to be here going forward."
The Conservatives had won 12 straight elections, but support for the rookie premier plunged during the campaign and right-wing voters split support between the Conservatives and the younger, more conservative Wildrose, which appeared on track to be the official opposition.
Prentice, who left investment banking to become party leader in September, had a 75 percent approval rating at the beginning of March. A poll this week showed his approval rating had dropped to 31 percent.
Dissatisfaction over Prentice's tax-raising budget, the expense of the early election call when the province faces a C$5 billion ($4.1 billion) budget deficit and a series of gaffes by the conservatives squandered the party's lead.
"This will go down as one of the biggest miscalculations in Canadian political history. He did not have to go early," pollster Bruce Cameron told CBC.
The historic win by the NDP, running in fourth place just a month ago, was met with disbelief on social media where even NDP supporters appeared stunned by the scale of the victory.
"Pigs must be flying all over Alberta," one user, @canadasean21, tweeted.
(Additional reporting by Andrea Hopkins in Toronto; Editing by Ken Wills and Amran Abocar)
