Sir Martin Sorrell's WPP (WPP.L) has announced that it has acquired US marketing agency Lunchbox via its wholly-owned subsidiary business JWT.

Los Angeles-based Lunchbox is a shopper engagement agency that works with retailers to create custom communications strategies influencing consumers on purchasing decisions at point of sale.

Its marketing activities centre around campaigns online, on mobile devices, on in-store video displays and through retail television networks played in store as well as direct advertising on point-of-purchase displays.

The business was founded in 2005 and currently employs 70 people with offices also in San Francisco and Chicago. It boasts a strong client list with a wide mix of blue chip and medium sized corporate clients including Unilever, Walmart and Kimberley Clark.

The company declared its unaudited revenues for the year ended 31 December 2010 as £13 million (US $21 million) with gross assets at the same date of £6.19 million (US $10 million).

Today’s announcement is further evidence of WPP’s ongoing acquisition strategy which is focussed on developing its client delivery channels and strengthening its content capabilities in the shopper marketing discipline.

It comes just days after the company acquired a majority stake in Indian advertising agency Mindset Advertising Private. This deal was also made through its global advertising network JWT.