The UK government is launching an inquiry into how online retailers use personal data to target consumers with individual prices for purchases like holidays, cars and household goods.
The Competition and Market Authority (CMA) has commissioned research to explore just how widespread the practice of targeting consumers through personalised pricing and search results is.
The probe will also examine the ways in which advertisers can use customer data and technology to enact "dynamic pricing"– including geography and marital status.
Dynamic pricing often means customers end up paying different prices for the same thing.
The competition watchdog wants to get a grip on how popular it is among brands and make sure the current system is "fair" for customers. It will also explore how personalised pricing is applied through different mediums like search engines and comparison tools.
"Ensuring markets work fairly and in the interests of consumers is a cornerstone of our modern Industrial Strategy, and I am proud to say that our consumer protection regime is among the strongest in the world," said business secretary Greg Clark.
"UK businesses are leading the way in harnessing the power of new technologies and new ways of doing business, benefitting consumers and helping them save money. But we are clear that companies should not be abusing this technology and customer data to treat consumers, particularly vulnerable ones, unfairly."
The CMA has launched several investigations this year around online marketing. Back in August, it announced plans to consider the extent to which influencer marketing was "clearly and accurately" identified online.
Its latest investigation into internet ads comes as the independent ad watchdog, the Advertising Standards Authority (ASA) has put online regulation at the heart of its five-year plan.