Twenty consumer and citizen rights groups have published an open letter [PDF] urging regulators to pay closer attention to Google parent Alphabet's planned acquisition of Fitbit.
The letter describes the pending purchase as a "game-changer" that will test regulators' resolve to analyse how the vast quantities of health and location data slurped by Google would affect broader market competition.
"Google could exploit Fitbit's exceptionally valuable health and location datasets, and data collection capabilities, to strengthen its already dominant position in digital markets such as online advertising," the group warned.
Signatories to the letter include US-based Color of Change, Center for Digital Democracy and the Omidyar Network, the Australian Privacy Foundation, and BEUC – the European Consumer Organisation.
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Google confirmed its intent to acquire Fitbit for $2.1bn in November. The deal is still pending, subject to regulator approval. Google has sought the green light from the European Commission, which is expected to publish its decision on 20 July.
The EU's executive branch can either approve the buy (with or without additional conditions) or opt to start a four-month investigation.
The US Department of Justice has also started its own investigation, requesting documents from both parties. If the deal is stopped, Google will be forced to pay a $250m termination fee to Fitbit.
Separately, the Australian Competition and Consumer Choice Commission (ACCC) has voiced concerns that the Fitbit-Google deal could have a distorting effect on the advertising market.
"Buying Fitbit will allow Google to build an even more comprehensive set of user data, further cementing its position and raising barriers to entry for potential rivals," said ACCC chairman Rod Sims last month.
"User data available to Google has made it so valuable to advertisers that it faces only limited competition."
The Register has asked Google and Fitbit for comment. ®