The $2.7bn figure (£2.1bn, €2,4bn) is the largest EC penalty to date, and will be imposed by the commission for breaking EU competition law. The commission says Google unfairly promoted its own Shopping service at the expense of smaller price-comparison sites.
The ruling may also demand that Google changes its search results so that it's not seen to favour its own service.
Google is ordered to end its anti-competitive practices within 90 days or face a further penalty.
Google argued that its Shopping service has been good for both retailers and consumers, and says that it is not a monopoly player in online shopping. It has stated that that its own shopping results "have not harmed the competition".
The fine itself is small change for Google, whose parent company Alphabet currently has more than $172bn of assets. However, the company could be more concerned with the impact on future operations.
Chris Green, from the tech consultancy Lewis told the BBC, "If it has to change the appearance of it results and rankings, that's going to have an impact on how it can monetise search.
"Right now, the way that Google prioritises some of its retail and commercial services generates quite a lot of ad income.
"When you consider the sheer number of search queries that Google handles on a daily basis, that's a lot of ad inventory going in front of a lot of eyeballs.
"Dent that by even a few percentage points, and there's quite a big financial drop."
Google's share priced dropped by 1.42% this morning.
Shivaun Raff, CEO and Co-Founder of Foundem, the lead Complainant in the European Commission’s Google Search case, made a full statement on searchneutrality.org. In it, she takes issue with Google's practice of pushing users towards its own revenue-generating paid search results.
"Convincing users that it is in their best interests to forego relevance-based natural search results in favour of pay-for-placement advertisements and artificially promoted links to Google’s own services is a tough sell.
"There is now a growing chasm between the enduring public perception of Google’s search engine as comprehensive and unbiased and the reality that, for commercial search terms at least, it is increasingly neither.