Real estate site Zillow, Inc. officially announced that it is selling its common stock. The company filed a registration statement with the SEC for an initial public offering (IPO) today. This long-awaited announcement does not include the number of shares up for sale nor the expected price range, because, per SEC rules, Zillow’s filing is in a waiting period, and essentially under a gag order, until the registration form S-1 is approved.

The co-managers handling Zillow’s IPO include Needham & Company LLC, ThinkEquity LLC, Allen & Company, and First-Washington Corporation.

Zillow, Inc. manages various real estate websites including Zillow Mobile, Zillow.com, and Zillow Mortgage Marketplace. This filing comes nearly a year after Zillow announced it wanted to seek IPO status.

As part of the IPO offering, Citi is working as the only book-running manager. Interested parties can obtain a preliminary prospectus by contacting Citi by calling 800-831-9146 or by writing to Brooklyn Army Terminal, 140 58th Street, 8th floor, Brooklyn, NY 11220.