These concerns were not eased despite today's report that sales of cars and light trucks by domestic makers rose in the recent 10-day selling period.

But however strong their sales were before the season officially opened, the shorter selling period has increased the anxiety of retailers.

For one thing, the back-to-school selling period looms larger in importance than it did before.

There were eight selling days during the last selling period of the year, compared with nine a year earlier.

Profits would vary, depending on how bond prices fluctuate during the selling period.

Still, some retailers said they expected the shorter selling period to trim business no matter how strong the Thanksgiving weekend was.

But the sale by the city of some middle maturities was soft, causing it to extend the selling period.

The price would only be fixed at the end of the selling period, generating some uncertainty for the issuer.

"The numbers for the first quarter of their next fiscal year, reflecting the back-to-school selling period, are the ones that will be important."

Car sales in the first two selling periods were off 37.9 percent.