GM shares were last up 2.2 percent at $36.72 before being halted.
GM said it will close three North American auto assembly plants next year: the Oshawa plant in Ontario, Canada; Hamtramck in Detroit, Michigan and Lordstown in Warren, Ohio. The plant is used to make the Cadillac XTS and Chevrolet Impala sedans as well as the Chevrolet Silverado and GMC Sierra trucks. GM will discontinue the Cruze in the USA market by 2019.
The five North American plants affected by the move are the assembly plants in Detroit-Hamtramck and Lordstown, Ohio, as well as the one on Oshawa, Ontario, and the two engine and transmission production plants in Baltimore, Maryland, and Warren, Ohio, all of which employ some 14,500 people.
Prime Minister Justin Trudeau said Monday the federal government will also do what it can to help laid-off GM workers "get back on their feet", while federal Innovation Minister Navdeep Bains said Ottawa stands ready to assist those workers any way it can.
The company said the plan would make it more efficient, saving $6 billion a year by the end of 2020.
Drama of a different kind was unfolding on the other side of the Pacific, with Japanese auto maker Mitsubishi confirming it had removed Carlos Ghosn as chairman.
GM's news release focused on the financial savings to the company that it predicts will come through these layoffs.
GM in recent years has worked to slice costs, with a goal of $6.5 billion in cuts this year alone.
GM said it is cutting production of several auto models, including the compact Chevrolet Cruze, as part of a massive restructuring that will eliminate about 5 percent of its North American workforce. Executive ranks will also be whittled down by 25 percent to streamline decision making.
Chiodo points out GM has yet to officially announce a plant closure - just that there will be no product.
Besides Ottawa and OH - a critical swing state for the 2020 USA presidential campaign - GM will shut down the Detroit-Hamtramck factory in the US state of MI. The company, which came out of bankruptcy only a few short years ago, has to take steps to remain "lean" and "agile", according to its CEO.
"This callous decision by GM to reduce or cease operations in American plants, while opening or increasing production in Mexico and China plants for sales to American consumers, is, in its implementation, profoundly damaging to our American workforce", said Terry Dittes, UAW vice president. Customers are increasingly shunning sedans in favor of SUVs and hatchbacks.
Federal and provincial politicians also weighed in on the reported closure, expressing concern for the thousands of high-paying jobs at the Oshawa plant - as well as the potential trickle-down effect a closure could have. That means GM needs to allocate more resources to purely electric cars, unlike the hybrid Volt, and to autonomous technology, Barra said.
This announcement comes less than a week after the Drive It Home campaign, which was a call to GM to reinvigorate production in the Lordstown plant. Did they announce the plant's closure with every intention of reaching some sort of deal with the White House to reopen it again - a kabuki closure, if you will? Consultancy LMC estimates that Lordstown operates at just 31 percent of production capacity in 2018.
The company has said the additional tariffs have cost GM more than $1 billion.