Google could end the year with a celebratory bang: a slew of dropped antitrust allegations about its core business.

Federal investigators have been on Google’s case for a long time about its allegedly illegal business practices when it comes to search results, but some insiders say the FTC might have less antitrust evidence than it had hoped for.

Anonymous sources told Reuters today FTC investigators are not certain they’ve got enough dirt on the search giant to seal a conviction.

Google has been under fire for more than a year for how it treats Yelp reviews and similar content from other sites. The search engine and its corresponding Places product will simultaneously pull in content from Yelp to flesh out review sections on Google Places. However, Yelp results may be artificially downgraded on search results pages, upstaged by less relevant results from Google’s own web properties.

“We believe Google has acted anti-competitively in at least two key ways: by misusing Yelp review content in their competing Places product and by favoring their own competing Places product in search results,” wrote Yelp CEO Jeremy Stoppelman in a blog post last year.

As anonymous FTC sources noted to Reuters, search rankings and Google’s famous search algorithm are the core of Google’s business and have been since its inception. If the FTC probe yields enough damning evidence, the case could have serious ramifications for the company — and if not, the company’s executives and shareholders will be breathing much easier come 2013.