New Delhi, Dec. 26 :    New Delhi, Dec. 26:  WPP, the world's largest advertising conglomerate with revenues of $ 17 billion, is bringing one more group affiliate to India - Red Cell. Red Cell, which is dubbed as its challenger network, will enter the country in March when it ties up with Equus, the Rs 62 crore boutique ad agency run by the Seth brothers - Suhel and Swapan. WPP will also be raising its stake in Equus to 45 per cent from 30 per cent from January 1. The Seth brothers will also be raising their stake in the ad firm they founded six years ago from 40 per cent to 55 per cent. This is being made possible by the decision of Korad, the Korean ad conglomerate, to pull out of Equus and offer its 30 per cent stake equally to WPP and the Seth brothers. WPP directly holds its stake in Equus unlike its other affiliate firms in India like HTA, O&M and Contract in which the stake is held through its network agencies. Early this week, WPP received an approval from the Foreign Investment Promotion Board (FIPB) to raise its stake in HTA to 74 per cent from 60 per cent at an investment of Rs 57 crore. The stake in HTA is held by J. Walter Thompson. WPP owns a 51 per cent stake in O&M, through its network of O&M world-wide. In Contract, it has a stake of 40 per cent through J. Walter Thompson. Equus chief executive Suhel Seth said, 'For Equus, the idea is to come into the Red Cell network which at present does not have affiliation with any ad agency in India.' Seth said the hike in WPP's stake in the ad firm would 'mean greater partnership between WPP and Equus'. Asked if the alliance with Red Cell would lead to any dilution of the Seths' stake in the ad firm, he said there has been no decision on this. He also refused to say how much the Seth brothers would invest in the ad firm to raise their stake. WPP has been steadily expanding its operations in India. Indian agencies like Rediffusion DY&R and Everest have also come into the WPP fold after the ad conglomerate acquired the Young & Rubicam network world-wide. Last year, it also picked up a majority stake in RMG David, a sister agency of O&M. Apart from advertising agencies, WPP in India also has stake in communication consultancy Quadra Advisory, corporate communication firm Burson-Marsteller Roger Pereira Communications Pvt Ltd and research agency IMRB.