The Washington Post https://www.washingtonpost.com/news/the-switch/wp/2017/05/23/google-now-knows-when-you-are-at-a-cash-register-and-how-much-you-are-spending/ reports that Google has talked retailers into sharing data from credit card transactions, which it will link to location and other data, to further enhance consumer profiling*.

The article says "Google for years has been mining location data from Google Maps in an effort to prove that knowledge of people's physical locations could "close the loop" between physical and digital worlds. Users can block this by adjusting the settings on smartphones, but few do so, say privacy experts.

This location tracking ability has allowed Google to send reports to retailers telling them, for example, whether people who saw an ad for a lawn mower later visited or passed by a Home Depot. The location-tracking program has grown since it was first launched with only a handful of retailers. Home Depot, Express, Nissan, and Sephora have participated."

* and erode privacy.

The article also makes it clear than consumers don't get to opt-out, if they even find out their data has been shared.