The government may not be able to extend as much financing as initially planned under a $25 billion loan program aimed at helping auto and other companies make more fuel-efficient vehicles.

The Government Accountability Office (GAO) said in a report on Thursday the Energy Department has exhausted most of the credit subsidy needed to underwrite loans that so far have totaled only a third of available funds.

Subsidy costs were higher than anticipated due partly to the risky financial situation of companies that received some $8.4 billion in financing since 2009, GAO said.

Ford Motor Co received $5.9 billion in loans and Nissan Motor $1.4 billion. Fisker Automotive Inc received $529 million and Tesla Motors Inc got $465 million.

Most of the money loaned so far has gone to factory retooling projects aimed at making gasoline engines more efficient.

Nissan spent money on its new Leaf electric car. Tesla and Fisker are also investing in electric vehicle technology.

The Energy Department is currently considering 16 projects seeking $9.3 billion in loans that would require roughly $3.5 billion in subsidy costs.

The credit subsidy balance was originally $7.5 billion. It now stands at $4.2 billion.

Chrysler, which is under management control of Fiat SpA, is seeking some $3.5 billion in loans. The company has yet to qualify for financing.

General Motors Co, which like Chrysler received a government bailout and restructured in bankruptcy, withdrew its $14 billion loan application this year after deciding to finance advanced technology projects without government help.

(Reporting by John Crawley; Editing by Gary Hill)

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