Google Inc.'s stock plunged suddenly on Thursday afternoon after a contractor released the search company's third-quarter earnings report early, by mistake.

The stock fell $68.19, or 9 per cent, to $687.30 before trading was halted to give investors a chance to digest the news. Google's report had been slated for release after the close of regular trading Thursday. The loss works out to be about $19B.

Google said printer R.R. Donnelley & Sons Co. filed Google's quarterly statement early to the Securities and Exchange Commission. The printer didn't immediately respond to a request for comment.

In the regulatory filing, Google said it earned $2.18 billion, or $6.53 per share, during the three months ending in September. That compared with net income of $2.73 billion, or $8.33 per share, last year.

The earnings would have been $9.03 per share, if not for Google's accounting costs for employee stock compensation and restructuring charges related to the acquisition of Motorola. Analysts polled by FactSet were expecting $10.63 per share, on average.

Revenue climbed 45 per cent from last year to $14.1 billion. Excluding compensation for websites that generate traffic for Google's ads, revenue was $11.33 billion. Analysts were expecting $11.5 billion.