Yell, owner of Yellow Pages, received a boost yesterday as the Competition Commission revealed that its impending investigation of the UK classified directories market will include online resources.

The commission will look at whether to include online classified directories in its definition of the market, something Yell has been advocating.

Selling ad space in printed directories is worth about £850m a year. Analysts reckon the inclusion of internet search engines and other online resources could result in more lenient treatment for Yell.

The price Yellow Pages can charge firms to advertise in its directories has been regulated since a review in 1996. When news of the latest inquiry was announced in April, Yell's shares fell 10% to 400p. Yesterday the stock gained 10.75p to 451.75p.

The watchdog will report preliminary findings in February with a final decision in June.