Advertising group Interpublic has emerged as a shareholder in Facebook. The company’s stake in the social network is valued at between $200m (£124m) and $300m. Interpublic is said to own slightly less than half a per cent in Facebook and paid less than $5m for it in 2006. Interpublic won the right to invest in what was then an emerging site by commiting to spend $10m of it clients’ cash on Facebook. Based on a recent valuation of Facebook at a staggering $50bn, the Interpublic stake of 0.4 per cent would be worth around £200m.