Bloomberg reports that, after four years of negotiations, Google purchases a trove of credit card transaction data from Mastercard, allegedly for “millions of dollars.” Google then reportedly used that data to provide select advertisers with a tool called “store sales measurement” that the company quietly announced in a blog post last year, though it failed to mention the inclusion of Mastercard data in the workflow. The tool can track how online ads lead to real-world purchases, and that extra data is designed to make Google’s ad products more appealing to advertisers. (Read: everybody makes more money this way.) The public was not informed of the reported Mastercard deal, though advertisers have had access to the transaction data for at least a year, according to Bloomberg.

This is a hell of a bombshell, when you think about it. Thanks in part to heavy government regulation, your credit card and banking data has long been private. If you wanted to spend $98 at Sephora on a Tuesday afternoon, that transaction was between you, your bank, and Sephora. It now appears that Google has found a way to weasel its way into the data pipeline that connects consumers and their purchases. If you clicked on a Sephora ad while logged in to Google in the past year and then bought stuff at Sephora with a Mastercard in the past year, there’s a chance Google knows about that, at least on some level, and uses that data help its advertisers stuff their coffers.

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This Orwellian ad engine does exist in Google’s new tool. Given the secrecy surrounding Google’s alleged Mastercard-assisted ad program, however, it’s hard to know what other tech giants are doing with our personal financial information. Amazon certainly knows a lot about the things we buy, and we learned earlier this year that the online retail giant was exploring the possibility of getting into the banking business itself. The Wall Street Journal has also reported that Amazon, like Facebook and Google, has had conversations with banks about gaining access to personal financial information.

Source: Google Reportedly Bought Your Banking Data in Secret, and That’s Not Even the Bad News