How Amazon strong-arms partners using its power across multiple businesses

Amazon.com Inc. last year told smart-thermostat maker Ecobee it had to give the tech giant data from its voice-enabled devices even when customers weren’t using them. The Canadian company said no.

The smaller company feared that complying with the demand would violate customer privacy, said a person familiar with the episode. Ecobee’s devices work with Alexa, Amazon’s voice-powered assistant, and it already shared some data with Amazon, the person said. Moreover, the company worried Amazon would glean insights from Ecobee’s users that it could use in competing products.

Amazon responded that if Ecobee didn’t serve up its data, the refusal could affect Ecobee’s ability to sell on Amazon’s retail platform, the person said.