The move makes the UK the first country outside the US to adopt the platform, which sells ad space on Asda's sites. It allows advertisers to target products at customer groups whose user profiles suggest they may be interested in a particular brand’s products.
The technology became available last year, though Asda has only now made its use public. Asda said that participating brands, which include Lucozade, had so far seen up to seven times the UK average click through rate.
As well as Asda’s main site, the data will become available to brands advertising on the supermarket’s magazine site, Good Living, and social platforms such as its YouTube channel.
Alex Crowe, head of Asda Media Partnerships, said: "Data that is actionable and provides new insight is at the forefront of every advertiser’s mind.
"Our WMX solution puts our unique, valuable data in the hands of brands, allowing them to make informed, highly targeted decisions when building out their media strategies on our digital platforms. What’s more, we live by this too — it’s the same data that Asda uses to reach its own target audience."
Asda appointed Triad Retail Media as its digital media sales agency in May 2015, replacing incumbent Publicis Blueprint, shortly after it began selling unsold ad units programmatically for the first time.
Jill Orr, executive vice president international at the agency, said: "This is a great example of how digital retail media can benefit advertisers.
"Not only does advertising on retail platforms enable better targeting informed by purchase behaviour, it also introduces the ability to create brand awareness and can personalise the customer experience when they are in a shopping mindset."