General Motors Corp has failed to persuade enough bondholders to accept a debt-for-equity swap, setting the stage for the largest-ever U.S. industrial bankruptcy within days.

The event marks a critical disappointment for GM, the largest U.S. automaker and once considered the bellwether of U.S. manufacturing. A popular ad for the automaker once stated that What's good for General Motors, is good for the USA.

I would say this is a sound rejection of an unsuitable offer, said Pete Hastings, a credit analyst at Morgan Keegan who has followed GM. I have been saying for some time that this thing was dead on arrival and we were just waiting for the doctor to pronounce it dead. Now that's happened.

The largest U.S. automaker had so far failed to gain anywhere near the 90 percent of bondholder support desired to stave off bankruptcy, two sources familiar with the discussions told Reuters on Tuesday. Bondholders have until midnight to make their final decision on the tender.

As of midday Tuesday, the source said the company had only a low-single-digit percentage interest from bondholders.

But bondholders have balked at proposals that they forgive debt in exchange for a 10 percent stake in a restructured company.

GM had no comment on the bond exchange. The automaker said it would detail results of the exchange on Wednesday morning. Reuters sources said GM could file for bankruptcy some time after midnight Tuesday, but before June 1.

THE WAITING GAME

While the failure to reach a bondholder deal is a severe blow, GM did reach an agreement on Tuesday with the leadership of the United Auto Workers (UAW) union.

The key for GM's negotiations with the UAW has been how the two sides restructured payment terms on $20 billion that the automaker still owes to a trust fund for retiree health care (the Voluntary Employee Beneficiary Association, or VEBA).

The UAW agreed to take 17.5 percent of common stock in a restructured GM, a person familiar with the terms told Reuters.

The union would also be paid $6.5 billion in preferred stock and would be granted a $2.5 billion note.

A deal on those terms would mean that the union was successful in taking on less risk than it would have under an earlier proposal from GM that would have given it 39 percent of the automaker's common stock.

As part of the plan, GM will offer buyouts to all UAW employees. Workers with 20 years or more will be offered $115,000 and a $25,000 voucher toward purchase of a new GM vehicle.

The UAW rank-and-file will vote on the contract on Wednesday and Thursday. Union officials who met in Detroit on Tuesday unanimously endorsed the pact after a briefing with UAW President Ron Gettelfinger, a person at the meeting said.

Current shareholders would be left with just 1 percent of a restructured company.

It's a slap in the face, said James Yarbrough, a retired accountant from Plano, Texas, referring to the 10 percent equity stake offer.

Yarbrough has invested $158,000 in GM bonds, which he first bought in 1994. He regrets buying more bonds in 2008, when he thought GM was about to make a turnaround.

This will probably force me to sell my house, Yarbrough said. I'm going to fight until the end.

A person familiar with Obama administration's thinking on the matter said the White House was continuing to engage with bondholders to reach agreement.

GM shares, which could be worthless in a bankruptcy, were recently down 3 cents at $1.40 on the New York Stock Exchange on Tuesday. The shares have traded between $1.84 and $1.12 on the day.

The U.S. government has provided a combined $36.6 billion to GM, Chrysler and their financing units since December.

In an interview broadcast over the weekend, Obama said he hoped GM and Chrysler would emerge from restructuring leaner, meaner, more competitive.

Chrysler is seeking approval this week to sell itself to a New Chrysler owned by the U.S. and Canadian governments, Chrysler's union and Italian carmaker Fiat SpA. A hearing on the sale will take place on Wednesday.

On Tuesday, a U.S. federal judge denied a request by a group of Indiana pension funds to delay the company's sale hearing and remove the bankruptcy case to district court.

SUPPLIER SIDE

The U.S. auto companies' struggles have also hurt the companies that make vehicles' components.

U.S. auto suppliers will be in dire need of up to $8 billion in emergency government aid over the next few months particularly if GM enters bankruptcy, Michigan Gov. Jennifer Granholm said.

We need to provide the (auto) suppliers with the means to get through the next 60 to 90 days, Granholm said at a press conference in Detroit.

Flanked by Michigan Congressman Sander Levin and Ed Montgomery, who is spearheading efforts to help communities suffering from the U.S. industry's worst downturn in decades, Granholm said she has asked the Obama administration for aid for suppliers.

She said that nationally there is an unmet need for $8 billion in aid for auto suppliers. Much of that aid will be needed in Michigan.

THE OPEL SAGA

While much attention is on Washington and Detroit, talks continue in Europe over the possible sale of GM's Opel unit.

On Tuesday, Germany pressed three bidders for Opel to improve their offers for the carmaker, saying they needed to assume greater risks and make credible commitments to preserve jobs and sites.

Economy Minister Karl-Theodor zu Guttenberg told reporters after meeting Fiat Chief Executive Sergio Marchionne in Berlin that the Italian carmaker's offer looked serious but that rival bidders Magna and RHJ International remained in contention.

There's no favorite, he said. Everyone knows that improvements are still necessary.

In an unexpected twist, China's Beijing Automotive Industry Corp (BAIC) also submitted an offer, potentially turning the three-way race into a four-way battle.

Fiat made an aggressive last-ditch push to convince the German government to back its bid for Opel ahead of a top-level meeting in Berlin on Wednesday where a preliminary decision on preferred bidders is expected.

Marchionne met with Chancellor Angela Merkel and Guttenberg on Tuesday morning to try to address German concerns about his ambitious plan to fold Opel into a transatlantic car empire that would also include U.S. carmaker Chrysler.

The German government hoped to be able to settle on one or more preferred bidders late Tuesday or Wednesday, a step which could lead to further negotiations.

Pressure to choose a preferred bidder is building ahead of the June 1 restructuring deadline for GM.

Across the border in Canada, GM workers at plants in Ontario on Monday ratified concessions negotiated last week with a vote of 86 percent in favor.

(Reporting by Jui Chakravorty and Kevin Krolicki; additional reporting by John Crawley, Walden Siew, Andreas Moeser, Noah Barkin, David Lawder, Emily Chasan and Nick Carey; editing by Patrick Fitzgibbons and Matthew Lewis)

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