Both retailers have been running campaigns with geotargeting network xAd, claiming an uplift in store visits.
The xAd network tracks consumers’ device IDs and locations, using that information to deliver precisely targeted advertising.
The company also offers analytics for brands to track the efficiency of a particular campaign in driving footfall.
Asda and Starbucks ran an initial set of campaigns to raise brand and product awareness, with both claiming improved footfall when trialling the ad format.
Rather than measuring click-through rates on mobile banner ads, xAd measures what it calls "store visitation lift" – in other words, whether more customers came through the doors. The company claims retailers experienced a lift in excess of 60% on average in store visits after running campaigns.
Ian Cranna, Starbucks’ EMEA marketing chief, said: "Historically reliant on click-through rates, the mobile industry has struggled to showcase the full impact and potential of the mobile channel.
"Starbucks prides itself on being a mobile innovator and we strongly believe in the use of the channel to engage potential and existing customers."
Chris Chalmers, head of digital marketing at Asda, said: "The trial has shown us the true potential for location-based campaigns.
"Early results show a real lift in store visits and we can see the impact of specific promotions which is critical in the run-up to Christmas."
An xAd spokeswoman told Marketing that both retailers would continue their partnerships beyond the trial, though she was unable to give specifics.
Separately, Asda’s partnership chief, Nick Bamber, recently told Marketing that the supermarket was trialling beacon technology at a small scale in an attempt to gauge consumer interest in highly targeted ads.