NEW YORK (CNN/Money) - General Motors was set to announce what it terms "significant developments regarding GM's business operations" Monday, after a night when GM and United Auto Workers union were holding talks on possibly trimming health care costs.

GM Chairman and CEO Rick Wagoner, who was scheduled to address GM employees at 8:30 a.m. ET, has been arguing since early this year the company needed to limit its health care expenses for union members, retirees and their families in order to stem losses at its core North American auto operations. There were media reports that there is an agreement between the two sides, although a spokesman with GM said he could not comment ahead of the official announcement.

Published reports last week said that GM (Research) was threatening the union with implementing changes unilaterally if it did not win concessions through negotiations. The union has said it would talk about changes in the health care coverage, but only within terms of the existing contract that runs through September 2007.

David Cole, chairman of the Center for Automotive Research, said in his talk with negotiation participants over the weekend suggested the two sides were getting very close to an agreement.

"The level of urgency that both sides felt in this is very, very high," he said. "I know it's reasonably imminent."

GM is also set to report its third quarter financial results at 8:30 a.m. ET. Analysts surveyed by earnings tracker First Call are forecasting a loss of 87 cents a share compared to earnings of 78 cents a share a year earlier.

Last week, Richard Shoemaker, the UAW vice president who is the lead negotiator with GM, told the Wall Street Journal that negotiations had been "constructive" and that both sides realize the talks "need to be brought to a conclusion in the near future."

GM is reportedly looking for changes that would trim $1 billion a year off of its operating costs out of the estimated $5.6 billion it is paying for health care coverage.

Beyond health care costs, GM is also facing problems due to the bankruptcy filing Oct. 8 of its former parts unit Delphi (Research). The company said at that time that it could face up to $11 billion in additional costs due to obligations to former GM workers at Delphi.

At least one analyst, Ron Tadross of Banc of America Securities, estimates there is now about a 30 percent chance of a bankruptcy filing at GM due to the additional costs from Delphi.

Both GM and Delphi, along with competitors Ford Motor Co. (Research) and DaimlerChrysler's (Research) Chrysler Group, face the costs of job guarantees for UAW members, who essentially can't be laid off during the life of the contract.

The Detroit News reported Monday that there are now more than 12,000 workers at those companies receiving pay of up to $31 an hour despite not having any work to do for the companies, including about 5,000 at GM and 4,000 at Delphi. There are also 2,100 at Chrysler and 1,275 at Ford, though that number is expected to climb with pending closure of its assembly plant in Lorain, Ohio.

For a look at the bankruptcy risk at GM, click here.