The chairman of Rightmove, Scott Forbes, has sold nearly half his shares in the company.

The timing of his sale – which has brought in some £7m for Forbes – has caused raised eyebrows, given Zoopla’s intention to join Rightmove on the stock market.

Forbes could also have made a lot more from his shares had he sold back in January. Shares in Rightmove have fallen in value some 15% this year.

No reason has been given for the sale by Forbes, who has chaired Rightmove since 2005 – the year before it floated on the stock exchange. However, there is speculation today that he may have sold the shares to raise money for a house purchase in Kensington.

This morning’s Telegraph says this would be “an apparent signal he does not believe the property market has reached its peak”.

In the deal, revealed in a stock market regulatory announcement to investors on Rightmove’s website, Forbes sold 300,000 shares for an average of £23.50. He is now left with 319,000 shares in the company.

News of the sale of shares comes days after Zoopla’s announcement that it intends to float in June.

And Agents’ Mutual is busy recruiting ahead of its portal launch next January, when it intends to disrupt the market currently dominated by the duopoly of Rightmove and Zoopla.

Until his appointment at Rightmove, Forbes was group managing director at Cendant Corporation, formerly the largest global provide of residential property services. He is chief executive of Bridge Capital Advisors, a firm he founded in 2007, and on the board of online travel company Orbitz Worldwide.

The Rightmove share price changed only slightly yesterday as the company continued to make its almost daily buy-back of shares. It finished yesterday at £23.40, up 9p, but well below the record high of £28.05 reached in January.

* If Zoopla and Rightmove look across the pond, they will see that shares in the USA’s major portal, Zillow, have been enjoying an astonishing run. From a low of around $25 early last year, the stock is now trading around the $120 mark.

Zillow has upped its profile with a national TV advertising campaign in a fragmented market and is beating off its nearest rival Trulia.