SOUTHFIELD, Michigan (Bloomberg) - General Motors Corp. (GM) said 7,500 United Auto Workers (UAW) members signed up for buyouts the company needs as part of cuts to keep $13.4 billion in US aid, more than doubling a Barclays Capital estimate.

The retirements and buyouts of 12 percent of GM's union workforce open slots for the Detroit-based automaker to hire replacement workers for half the current union rate. Under the federal loans GM says it needs to survive, labor costs must match those of Japanese automakers in the US. The company has trimmed about 60,500 jobs in three buyouts since 2005.

The latest reduction may save GM about $948 million annually, Barclays analyst Brian Johnson said in an interview. Johnson, who estimated 3,100 workers would take the offers, said the number was "a fairly decent uptake, considering there is less money on the table. But they probably still need more."

GM, the largest US automaker, and Chrysler LLC are encouraging workers to accept buyouts, retire or quit after concessions this year eliminated benefits related to job security and unemployment pay. The companies are seeking as much as $21.6 billion more in US aid to stay in business.

GM rose 41 cents, or 13 percent, to $3.40 at 1:43 p.m. in New York Stock Exchange composite trading. The shares tumbled 85 percent in the 12 months before today.

The company probably needs as many as 10,000 more workers to leave to maximize use of new employees, said Johnson, who is based in Chicago and rates the company's shares "neutral".

More than half of the GM workers signed up since March 20, and about 90 percent are either retirees or taking early retirement, company spokesman Tony Sapienza said in an interview. The workers will leave by April 1, and vacant jobs will be filled with existing workers where possible and new employees where necessary, GM said.

"We're pleased," Mr. Sapienza said. "This is a significant milestone in progress in our restructuring plan."

President Barack Obama said he plans to outline his strategy for the auto industry in the next few days and suggested he is open to providing carmakers with more aid.

"We need to preserve a US auto industry," Obama said today as he answered questions at an Internet town-hall event from the White House. The "current economic model of the US auto industry is unsustainable," he said.

Obama's auto task force will probably make more money available to carmakers, US Senator Debbie Stabenow, a Michigan Democrat, told reporters. Conditions are likely to include "downsizing" and continued restructuring, she said.

GM's union buyout covers about 62,000 employees willing to retire or quit and consists of a $25,000 voucher to buy a new auto and receive $20,000 in cash. The company's goal was to get half of about 22,000 eligible workers to leave, and GM budgeted for about 6,000 to take the current offer, a person familiar with the plans said.

Workers who accepted the buyout by the March 24 deadline have seven days to reconsider. The UAW declined comment on the offers before today's release.

GM, Ford Motor Co. and Chrysler cut more than 124,800 hourly workers with buyouts or attrition in three years.

Union workers at Ford, which is not seeking government loans, ratified changes March 9 after reaching an accord on a plan to replace as much as half of future payments to a UAW-run retiree health-care fund with stock instead of cash. GM and Chrysler are still negotiating retiree-fund changes.

The Ford UAW concessions eliminate the so-called jobs bank that paid workers most of their wages to report to a location when there were no duties to perform. Pay that supplements unemployment has been reduced. Laid-off employees who decline a new job, even hundreds of miles away, lose their benefits.

Ford's buyout program, which pays as much as $75,000 in cash and vouchers, begins April 1 and ends May 22.

The programme may be accepted by five percent, or about 2,100, of Ford's current 42,000 UAW members, Barclays's Mr. Johnson wrote.

Chrysler may shed about 3,000 workers in a buyout, people familiar with that programme said this week. The deadline for acceptances, originally set for tomorrow, has been extended indefinitely because new contract language with the UAW is not complete, company spokesman Max Gates said yesterday.

Cerberus Capital Management LP's Chrysler is offering cash and a vehicle voucher with a combined value of as much as $75,000 to its 28,600 UAW workers.

The Auburn Hills, Michigan-based automaker granted buyouts of as much as $100,000 last year, when 13,200 union workers left.

GM started the first of its announced plans for 10,000 salaried-worker cuts March 24, eliminating 160 mechanical engineering jobs in Michigan, spokesman Tom Wilkinson said. The automaker has a May 1 deadline to complete the reductions, which include 3,400 US employees.

The company got 34,400 union members to leave in 2006 with packages of as much as $140,000, and used pension funds to help pay as much as $62,500 for 18,000 UAW members to depart in 2008.

More than 4,000 of the buyouts announced yesterday were at Michigan locations, according to a GM breakdown. The largest single group was 624 in Janesville, Wisconsin, where the company closed a sport-utility vehicle plant in December.