The seven domestic manufacturers reported sales of about 176,000 cars, up 13.9 percent.
The law does not even require manufacturers to report adverse effects to the government.
For the nine manufacturers reporting results today, sales dropped 2 percent.
Sales were up 5.7 percent from the comparable period a year earlier, the seven domestic manufacturers reported.
He added, "Manufacturers in both areas reported fading price pressures."
The search widened when some manufacturers reported not using Chinese milk.
And manufacturers of snow blowers have reported a 20 percent decline in business.
Even manufacturers reported a slow expansion in recent months.
The country's five manufacturers reported sales of 313,870 vehicles.
And manufacturers report a big drop in new orders.