Google (Nasdaq: GOOG), the No. 1 search engine, reported third-quarter net income and revenue that fell well-below expectations. The premature announcement came in a federal filing, rather than in a release after the Thursday market close.

Shares of the Mountain View, Calif., have plunged more than 10 percent after the error. In midafternoon, they tumbled to $687.30, down $69.19, or 9 percent.

Third-quarter net income was only $2.18 billion, or $8.33 a share, compared with $2.73 billion, or $8.33 a year ago. Revenue rose to $11.33 billion.

Analysts had expected Google to report net income to rise nearly 10 percent to $3.45 billion, $10.65 a share on an operating basis. On that basis, income was only $9.03 a share.

The company sent its results early to the U.S. Securities and Exchange Commission but the text of the announcement included the words “pending Larry quote,” a reference to CEO Larry Page, whose remarks would appear with the earnings announcement.

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