Motoring group AA posted half-year profits sharply down from a year ago, hurt by financing costs linked to its stock exchange listing in June.

But executive chairman Bob Mackenzie said the company's maiden first-half results reflected only a few weeks of operations under the new ownership and that full-year profits were likely to be in line with market expectations. 

The AA's shares have soared 28% since their listing at the end of June. 

The AA - best known for its roadside recovery service - said profits before tax fell to £10.2m in the six months to the end of July, down sharply from £121.2m the previous year. 

"There is some distorted effect to the profit before tax due to the one-off costs of the IPO and we had a full-year interest charge from the refinancing," Mackenzie said. 

Exceptional costs were £39.4m, up from £10.2m in 2013, after financing costs increased to £138.6m from £47.1m. 

The AA, which also sells insurance, has a long-term growth plan based on updating its IT systems, Mackenzie said. 

"There is an awful lot of data that we do not use - we need to start using that data in setting (insurance) premiums," he said. 

The AA went public after a sale by its private equity owners to a management buy-in team led by Mackenzie, a former boss of car insurer Green Flag, backed by institutional investors.