Google overnight confirmed reports that European regulators are looking into complaints that it's unfairly pushing down the rankings of some of its competitors in its search results. The company denied wrongdoing, and pointed out that Microsoft is connected to two of the three companies making complaints.

One is a price-comparison service called Foundem, which is a member of a Microsoft-funded organization called ICOMP, the Initiative for a Competitive Online Marketplace. Foundem has been outspoken on the subject of "search neutrality" in that role. Another is a similar service called Ciao!, renamed Ciao! from Bing after it was acquired by the Redmond company. Google said it "always had a good relationship" with Ciao, but started receiving complaints from the company after Microsoft's acquisition.

"Though each case raises slightly different issues, the question they ultimately pose is whether Google is doing anything to choke off competition or hurt our users and partners. This is not the case," writes Julia Holtz, Google senior competition counsel, in the blog post. "We always try to listen carefully if someone has a real concern and we work hard to put our users' interests first and to compete fair and square in the market. We believe our business practices reflect those commitments."

David Wood, the legal counsel for ICOMP, offerd the group's take in a blog post this morning.

"A significant part of the concern about Google’s practices stems from a lack of transparency as to how Google operates. Google is, of course, entitled to protect its own intellectual property and business secrets," he wrote. "However, given its dominant position in search and search advertising, it is also under a special responsibility not to harm its competitors."

More coverage: TechCrunch, Wall Street Journal, and San Francisco Chronicle.