MOUNTAIN VIEW, Calif. ( TheStreet) -- European antitrust authorities have opened a preliminary probe into complaints by three European Internet companies about Google's ( GOOG) tactics of lowering their rank in search results that appear on Google sites, Google revealed.

Julia Holtz, Google's senior competition counsel, wrote in a blog post that the EU has received complaints from a U.K. price comparison site, Foundem, a French legal search engine called ejustice.fr and Microsoft's ( MSFT) Ciao! from Bing.

Foundem argues that Google's algorithms demote their site in the search results because it is a vertical search engine and so a direct competitor to Google. Ciao! has complained about Google's standard terms and conditions.

"While we will be providing feedback and additional information on these complaints, we are confident that our business operates in the interests of users and partners," Holtz wrote.

Follow TheStreet.com on Twitter and become a fan on Facebook.

If you liked this article you might like

Using Twitter to Trade Stocks

Using Twitter to Trade Stocks

Alphabet Is the Best Tech Stock to Own After the Correction

Alphabet Is the Best Tech Stock to Own After the Correction

Why I Like Amazon, Apple and These Other Stocks for February

Why I Like Amazon, Apple and These Other Stocks for February

The Best Jobs in America

The Best Jobs in America

2018 Super Bowl Ad: Kraft Attempts to Make 'Family' a Verb

2018 Super Bowl Ad: Kraft Attempts to Make 'Family' a Verb