FILE - This May 16, 2014, file photo shows the General Motors logo at the company's world headquarters in Detroit. The United Auto Workers union is letting its contract with General Motors expire just before midnight Saturday, Sept. 14, 2019, increasing the likelihood of a strike as early as Sunday night. (Photo: AP) 

M, which is more profitable than Ford and Fiat Chrysler, as the target company, meaning it’s the focus of bargaining and would be the first company to face a walkout. Picket line schedules already have been posted near the entrance to one local UAW office in Detroit.

Talks between the union and GM were tense from the start, largely because GM plans to close four U.S. factories, including the ones in Detroit and Lordstown, Ohio. The union has promised to fight the closures.

Here are the main areas of disagreement:

— GM is making big money, $8 billion last year alone, and workers want a bigger slice. The union wants annual pay raises to guard against an economic downturn, but the company wants to pay lump sums tied to earnings. Automakers don’t want higher fixed costs.

— The union also wants new products for the four factories GM wants to close. The factory plans have irked some workers, although most of those who were laid off will get jobs at other GM factories. GM currently has too much U.S. factory capacity.

— The companies want to close the labor cost gap with workers at plants run by foreign automakers. GM’s gap is the largest at $13 per hour, followed by Ford at $11 and Fiat Chrysler at $5, according to figures from the Center for Automotive Research. GM pays $63 per hour in wages and benefits compared with $50 at the foreign-owned factories.

— Union members have great health insurance plans but workers pay about 4% of the cost. Employees of large firms nationwide pay about 34%, according to the Kaiser Family Foundation. The companies would like to cut costs.