Private equity group Alchemy Partners sold 12.9 million shares, or a 5.9 percent stake, while an unnamed institutional investor sold 5 million shares, the source said.

Countrywide has benefited from a pick-up in British house prices over the past 12 months, aided by government schemes to lower banks' borrowing costs and help home buyers struggling to find large deposits for mortgages.

Data on Friday showed that British house prices shot up at their fastest annual rate in more than three years in September, though the pace of the market's recovery has raised concerns about an unsustainable house price boom.

Countrywide's share price has risen by about 50 percent since its return to the stock market in March. The group owns 46 brands, including Hamptons International, and on Thursday announced a move into commercial property with the proposed purchase of Lambert Smith Hampton for 34.1 million pounds.

The stake sales by Alchemy and the unnamed institutional investor were at 525 pence per share, a 3.6 percent discount to Thursday's closing market price. By 0905 GMT Countrywide shares were down 4.2 percent at 521.5 pence.

Countrywide was not immediately available for comment.

The group's other two private equity owners, Oaktree Capital and Apollo Global, last month sold shares worth a total of 200 million pounds.

(Reporting by Kylie MacLellan and Tom Bill; Editing by David Goodman)

Stocks treated in this article : Countrywide plc, Countrywide PLC