Cyber Monday was the biggest shopping day in Amazon’s history. Turns out it was also a day for Amazon to promote its own brands over all others.

On Monday, asking an Amazon Echo for the “best Cyber Monday deals” returned five straight responses from smart assistant Alexa that promoted products owned by Amazon:

a Blink security camera

a Ring video doorbell

another Blink security camera

an Alexa-powered Echo Dot, and

an Alexa-powered Echo Show.

Amazon acquired Blink, a maker of security cameras, in 2017; it purchased Ring, the maker of video doorbells, in 2018. An Amazon spokesperson told Recode that after those first five deals, Amazon did promote items made by other companies, and that Alexa-enabled non-Echo devices returned deals in their first five responses that included non-Amazon-owned items.

But the initial Alexa responses are just another sign of Amazon’s aggressiveness in promoting its own brands, whether they are gadgets like the Echo family of smart speaker products and Ring doorbells or apparel lines like Goodthreads. Amazon’s Black Friday deals also predominately featured Amazon’s own brands ahead of others, according to an analysis by Quartz.

The holiday promotions come at a time when politicians, regulators, and even Amazon’s own sellers are increasingly scrutinizing whether the e-commerce giant favors its own products over those made or sold by other merchants on its platform.

That potential favoritism can come in varied forms, including in Amazon search results, with prime placement on competitor brands’ product pages, and even right at checkout when an Amazon customer is ready to buy an item from a non-Amazon brand. This last tactic could be compared to a cashier in a physical store showing you a deal for the store’s own brand when you walk up to pay for a competitor’s product.

US lawmakers on the House Subcommittee on Antitrust, Commercial, and Administrative Law have also questioned Amazon about its use of Amazon sellers’ data to create products to compete with those very same sellers. And the European Union has initiated a formal antitrust investigation into Amazon to determine whether similar data use is anticompetitive.

Amazon has defended its data usage as well as its promotion of its own brands, pointing to traditional retailers’ longtime marketing of in-house brands.

“Consistent with the value proposition for private brands generally, Amazon knows from experience that Amazon’s private brand products have on average higher customer review ratings, lower return rates, and higher repeat purchase rates than other comparable brands in the Amazon store,” the company said in responses to questions from the House antitrust subcommittee that were published last month. “As a result, like other retailers, Amazon highlights its private brands in promotions and marketing in the Amazon store when Amazon thinks they will be of interest to customers. Of course, Amazon is the only seller of Amazon private brands in the Amazon store.”

That last, seemingly throw-away sentence, however, could inadvertently open up a whole new line of inquiry about Amazon’s treatment of its own brands. The obvious question: Since other brands typically can’t stop Amazon sellers from selling their brands on its platform, why should Amazon get that privilege?