Earlier this year, the European Union accused Google of monopolistic practices, alleging that, among other things, it unfairly prioritized its comparison shopping service when users searched for things to buy. Google has since commented on these charges — which could theoretically result in a fine of $6.6 billion — but has now issued a formal 130-page response, suggesting that the company is settling in for a long fight.

"No trading relationship exists between Google and its users."

According to a report from Reuters, the response marshals a number of legal arguments, including the assertion that Google can't take advantage of its customers because they don't pay for its services. "The [EU's] objections fails to take proper account of the fact that search is provided for free," says the document. "A finding of abuse of dominance requires a 'trading relationship' as confirmed by consistent case law. No trading relationship exists between Google and its users."

Many of Google's objections center around the EU's perceived failure to establish proper procedure in the case. The European Commission has been investigating the charges for five years and tried to settle with Google three times previously. In 2014, the EU said a third settlement was "capable of addressing [its] competition concerns," before performing a U-turn in September last year and asking for more money.

A slide from the EU's case explainer.

According to The Wall Street Journal, Google says that the EU needs to provide "reasons for the change in position," and claims that the Commission has not explained "why it found the January 2014 commitments insufficient." It adds that the case lacks legal precedent and that "the rules must be knowable in advance." Ultimately, says Google, the EU is demanding that it "sacrifice quality to subsidize competitors."

The EU's original complaint, however, claims the opposite is true, and that Google frequently ignored quality in order to bolsters its own failing services, lowering the search rank of rivals' stores and prioritizing its own results "irrespective of [their] merits." The case still has a long way to go though, with the EU not expected to make its decision until at least next year. Any ruling can then be challenged in the EU's court of appeals — a process that could take an additional five years.