WPP may be about to buy small digital ad firms such as SpotRunner, VideoEgg, Visible or JumpTap, reports the New York Post, after the ad giant admitted it was about to boost its digital assets. "We'll be making one or two announcements of further digital acquisitions," Sir Martin Sorrell says, adding that the purchases won't be "big ones." Over the past year, WPP has made a series of digital acquisitions, buying 24/7 Real Media for USD649m, 75% of Indian online media agency Quasar Media, and taking over Vancouver-based Blast Radius and US-based Schematic. The London-based ad group is also reportedly currently courting Montreal-based Nurun, another interactive ad firm. WPP is already a minority investor in both Spot Runner, which runs a TV ad network allowing advertisers to target ads by demographics or location, and in VideoEgg, which operates video ads. Both are VC-backed, with SpotRunner raising more than USD72m, including backing from WPP and CBS, whilst VideoEgg recently raised USD15m, in a round led by Focus Ventures. WPP has also previously invested in Visible, the social media monitoring firm, which raised USD12m in a funding round last Sep. JumpTap, which operates a mobile ad service, raised USD22m including investment from Valhalla Partners in 2006.