"We have not declared the registration statement effective," SEC spokesman John Heine said after the passing of Google's requested deadline of 4 PM (ET).
The company notified investors on Monday that the SEC and state regulators began an investigation of the company's unregistered issuance of 28 million shares to employees and consultants.
SEC approval is necessary before Google can price its 24.6 million shares for sale to the public. Google set a suggested price of between $108 and $135 per share several weeks ago; its IPO is expected to raise between $2.7 and $3.3 billion.