Motor trader Pendragon saw sales jump by a fifth in the third quarter as it said full-year results would be "materially ahead" of expectations.
Shares in the group, whose brands include Evans Halshaw and Stratstone, climbed 7% on the update, while their value has more than doubled in the past year amid strong signs of recovery on car forecourts.
It said retail volumes in the UK were up by 19.4% for the three months to the end of September, with a 15.6% increase in new car sales for the year to date.
Pendragon said it saw a 17th successive quarter of growth in used car volumes, and with market share continuing to increase a like-for-like rise of 9.7% for the quarter.
The update is in line with recent figures from the Society for Motor Manufacturers and Traders, which said UK car sales in September hit their highest monthly total for more than five years.
According to the SMMT, there were 403,136 new cars registered in the UK, a rise of 12.1% on the same month a year earlier.
Pendragon added that its service, maintenance and repair business was boosted by the return to growth in the new vehicle market as a whole. Retail labour sales grew 2.9%.
The group said its California business had also performed strongly, largely due to the success of Land Rover.
Elsewhere, the Quicks brand narrowed losses in the year to date with a small increase in volumes in the third quarter though there was a slight decline in margin.
The group saw website visits up 23.5% on the prior year for the nine months to the end of September.
It said: "Profitability in 2013 is expected to be materially ahead of expectations for the full year and we are cautiously optimistic about the prospects for 2014."
In 2012, underlying profits before tax were up 18% to £36.4 million on the previous full year.
Numis Securities upgraded its full-year profits estimate from £40 million to £44 million today, having previously pencilled in a £1 million decline in second half profitability year-on-year.