M&C Saatchi is to acquire half of Walker Media co-founder Phil Georgiadis's shares in the media planning and buying agency in a deal worth around £3m.

Mr Georgiadis, who co-founded Walker Media a decade ago, will retain approximately a 4.75% stake in the business.

He now runs the business as its chief executive and is to receive a cash payment of £2.14m. In addition he will take a shareholding in parent company M&C Saatchi worth £730,825.

Mr Georgiadis has elected to sell the stake two weeks after Christine Walker sold her 14% share in Walker Media to M&C Saatchi for around £9m.

Ms Walker's deal is a mix of cash and shares, worth around £2.2m, in the parent company.

She announced at the beginning of the month that she is to leave the company to pursue other interests at the end of June.

When the two deals are complete M&C Saatchi will control 93.75% of Walker Media.

Both deals will be subject to an adjustment payment - either up or down - in cash depending on the consolidated profit for Walker Media for the financial year ending December 31 2007.

Walker Media started trading in January 1998 as a 50/50 joint venture with M&C Saatchi.

In July 2004, M&C Saatchi acquired a further 25% of Walker Media's shares when the business floated on the AIM market.

Walker Media was valued at £18m in 2004, when M&C Saatchi increased its stake to 75%.

The agency has clients including Barclays, which spends around £70m per year on media and advertising.

· To contact the MediaGuardian newsdesk email editor@mediatheguardian.com or phone 020 7239 9857. For all other inquiries please call the main Guardian switchboard on 020 7278 2332.

· If you are writing a comment for publication, please mark clearly "for publication".