Prices for certificates of entitlement (COEs) finished lower at the close of the latest tender exercise yesterday in all categories except for commercial vehicles.

Auto dealers attributed the sliding COE premiums to the weaker economic sentiment, which is leading buyers to hold off purchases of big-ticket items.

The COE price for cars up to 1,600cc and 130bhp fell by 3.3 per cent, from $52,668 two weeks ago to $50,951. The premium for bigger cars - those above 1,600cc or 130bhp - registered the largest drop this round, falling by 5.7 per cent from $56,206 two weeks ago to $53,001 yesterday.

The COE price for the Open category, which can be used for any vehicle type but ends up mainly used for big cars, slid by 2 per cent. The premium in the segment dropped from $56,000 to $54,901.

Mr Nicholas Wong, general manager of Kah Motor, said jittery buyers stayed away from making bids.

In the large car category, for example, there were 1,708 bids received in the latest tender, down from 2,012 two weeks ago.

But weak sentiment is not the only reason for slower year-end sales. "There was also a car carnival at the (Singapore) Expo last month, and many people would have bought their cars then," Mr Wong said.

Many buyers are also on holiday. "So we have a vacuum now," he said.

While premiums for cars fell, the COE price for goods vehicles and buses bucked the trend, increasing by 2.1 per cent from $48,001 to $49,002.

Mr Michael Wong, director of Triangle Auto, the agent for Isuzu, said this was unusual, considering there was a larger COE supply in the period between November and January, compared with the previous quarter.

He said it was likely that orders had been placed earlier and had to be fulfilled now. He expects prices to soften next year, in the lead-up to Singapore adopting the more stringent Euro 6 standard for diesel vehicles in 2018.

Meanwhile, the COE price for motorcycles fell by 1.6 per cent, from $6,311 to $6,212.