General Motors Corp. (GM) expects to release a government-mandated recovery plan to the public after 6 p.m. on Tuesday, though the report might not include critical concessions from the company's labor unions and bond holders.

Chrysler LLC is working on a similar disclosure.

The two auto makers, surviving on $17.4 billion in federal aid, are required to submit detailed restructuring plans to the U.S. Treasury on Tuesday as a condition of the loans.

GM shares were down 14.8%, or 37 cents, to $2.13 in morning trading. The auto maker's stock has lost more than 90% of its value in the last year.

At GM, overnight negotiations with the United Auto Workers failed to produce a deal that would substantially cut labor costs, sources familiar with the talks said. Bargaining remained underway Tuesday morning.

The auto maker also is working to convince bond holders and other creditors to accept terms that will reduce its substantial debt.

GM said it will submit its restructuring plan regardless of whether is succeeds in cutting deals with the union or bondholders.

GM's plan, an 800- to 900-page report that explains how the auto maker can turn around operations that have lost more than $70 billion since 2004, is expected to detail plant closings, plans to eliminate models and brands and to further reduce structural costs.

UAW negotiations hinge on GM's efforts to change terms under which it pays the union to assume responsibility for billions in retiree medical costs.

The two sides made progress over the holiday weekend but were still hammering out significant differences, according to people familiar with the talks.

Ford Motor Co. (F) did not ask for government aid, though the auto maker is likely to seek concessions in line with what GM and Chrysler win.

-By Sharon Terlep; 248-204-5532; sharon.terlep@dowjones.com.