"What we think truly pushed a weak credit off the cliff was the inept working capital management during the last holiday season," he said.

This is the sign of a relatively weaker credit.

"Almost all scenarios leave it a weaker credit than it was before its dalliance with G.E.," she said.

The combination of winter weather and newly tightened lending standards for people with weak credit probably sped the drop, economists said.

In the United States, sales have been falling swiftly since the company stopped making car loans two years ago to customers with weak credit.

Higher volatility (a good thing) tends to accompany weaker credit (bad).

Economists and others who monitor the national scene ascribed the downturn to winter weather and tightened lending standards for people with weak credit.

But many experts say it is a message that can be drawn from the rising troubles with mortgages provided to home buyers with weak credit.

So while good managers can pick their way through weaker credits, many are choosing instead to buy high-quality muni bonds.

Some lawmakers have called for tighter restrictions on issuing loans to people with low incomes and weak credit.