Vodafone (NYSE: VOD) is ending its two-year exclusive mobile ad sales agreement with Yahoo (NSDQ: YHOO) when the deal expires in June in order to work with a number of mobile sales networks to boost its ad revenues from as many partners as possible, reports NMA.co.uk, citing an unnamed source at the British carrier. “We might collaborate but it won’t have exclusivity,” the source said. He also said that the carrier did not have plans to create its own in-house sales team.

Vodafone took its first steps to opening up its sales to more than one partner when it agreed in November to allow pay-TV broadcaster Sky to sell its own inventory on the Vodafone Live! portal. Sky wanted more control over the sales around its own content so it could offer its advertisers a “one stop shop.” But as NMA.co.uk writes, the new strategy for Vodafone could backfire on the carrier, as bringing more ad sales networks on board could be very confusing for buyers, who will have to sort through them to hunt for the best prices and best opportunities.

Still, the end of the pact is considered a blow to Yahoo, who has been pushing aggressively into the mobile space in pursuit of its own mobile ad sales revenues. In the UK, Yahoo still has two other exclusive mobile ad sales deals, one with T-Mobile, and one with Three UK.

• Report: Vodafone UK May Replace Yahoo As Mobile Ad Sales Partner