
The acquisition of Mysupermarket.com comes as WPP pursues a target of 35% to 40% of revenue to be derived from its digital assets – which include Wunderman, OgilvyOne and VML – within the next five years.
The stake is believed to form the lion's share of a $10m (£6.2m) round of funding for Dolphin Software, which also includes participation from existing investors Greylock and Pitango.
Mysupermarket.com employs 70 people and has offices in New York, London, Tel Aviv and Tokyo, with principal operations in New York.
Founded in 2006, the company operates a shopping site that allows customers to compare shopping baskets and buy from the major UK online grocery, and health and beauty retailers.