WASHINGTON – General Motors Co. is expected to announce today that it will begin repaying its debt to the United States next month, years earlier than required.

The nation’s largest automaker plans to pay $1 billion per quarter until the $6.7 billion loan is repaid, according to a source familiar with the matter.

The plan does not cover all of the $50 billion the United States has invested in the company, however.

How much the government will receive on its investment depends on GM’s eventual stock value. In exchange for the $50 billion, the United States holds the $6.7 billion debt, $2.1 billion in preferred stock and a 61 percent stake in the company.

But the announcement of the repayment plan indicates that GM – which has a truck assembly plant in Allen County and a foundry in Defiance, Ohio – has exceeded financial planners’ projections.

“This is a result of the company performing modestly above expectations,” said the source, who spoke on the condition of anonymity to discuss the situation. “Obviously, the company has a long way to go and a lot of important things to execute on.”

The repayment plan comes as the company prepares to post its first quarterly earnings report since emerging from bankruptcy proceedings in July.

The $6.7 billion debt is not due to be repaid until July 2015, but the company has exceeded projections, partly by going through bankruptcy more rapidly than it thought it would, and partly by cutting costs.

The company is not expected to be showing a profit when financial results are reported today. But it has significantly cut its operating costs and is better able to weather the downturn in auto sales that put it and Chrysler on the brink of ruin this year.

In its last quarterly earnings report, in May, the company said its had lost $6 billion and used $10.2 billion more in cash than it generated from operations.

The new earnings report, representing the restructured GM, will be issued at 7 a.m. today. It will be measured against those bleak statistics.