For the past year, select Google advertisers have had access to a potent new tool to track whether the ads they ran online led to a sale at a physical store in the U.S. That insight came thanks in part to a stockpile of Mastercard transactions that Google paid for.
But most of the two billion Mastercard holders aren’t aware of this behind-the-scenes tracking. That’s because the companies never told the public about the arrangement.
Google paid Mastercard millions of dollars for the data, according to two people who worked on the deal, and the companies discussed sharing a portion of the ad revenue, according to one of the people. The people asked not to be identified discussing private matters. A spokeswoman for Google said there is no revenue sharing agreement with its partners.
Last year, when Google announced the service, called “Store Sales Measurement,” the company just said it had access to “approximately 70 percent” of U.S. credit and debit cards through partners, without naming them.
Since 2014, Google has flagged for advertisers when someone who clicked an ad visits a physical store, using the Location History feature in Google Maps. Still, the advertiser didn’t know if the shopper made a purchase. So Google added more. A tool, introduced the following year, let advertisers upload email addresses of customers they’ve collected into Google’s ad-buying system, which then encrypted them. Additionally, Google layered on inputs from third-party data brokers, such as Experian Plc and Acxiom Corp., which draw in demographic and financial information for marketers.