The bidding has started for Google's high-profile public offering, despite last-minute worries over an interview with its bosses in Playboy magazine.
Founders Sergey Brin and Larry Page may have violated securities rules by courting the media, the company warned.
Firms traditionally avoid media interviews ahead of their stock market flotation to avoid accusations of hyping up the stock.
But Google said it would "vigorously" contest any such claims by regulators.
In an amended IPO document filed with the US Securities and Exchange Commission (SEC) just hours before the auction opened, the company did not say whether the possible violation would affect the flotation.
Nevertheless, the bidding has started.
Google, which hopes to raise as much as $3.5bn (£1.91bn) through the float, will announce the price of the initial public offering (IPO) next week.
The internet's most popular search engine has filed to sell 25.7 million shares - at an estimated price range of $108 to $135 per share - in a so-called Dutch auction.
In this type of auction, Google will take bids from hopeful investors, who will be required to state how many shares they want to buy and at what price.
The float price is then set by assessing bids from individual investors.
Google said it chose this method to give smaller investors better access to its stock.
In its filing with the SEC, Google said it did not believe its Playboy interview constituted a violation of the "quiet period" rules.
But it did warn that it could be forced to buy back the shares sold to investors in the IPO at the original purchase price for a period of one year following the violation.
Earlier this year, Salesforce.com ended up delaying its IPO after the company and its chief executive were featured in a New York Times article.