Days after raising $600 million in an initial public offering (IPO) to fund the construction of its nationwide mobile WiMax network, broadband wireless operator Clearwire saw its stock price dip by nearly 15% as investors turned around and sold Clearwire shares acquired through the IPO. With the help of its principal backers Motorola and Intel, Clearwire—a venture founded by cellular pioneer Craig McCaw—is betting its fortune on a new, nationwide mobile WiMax network that would offer high speed wireless Internet connectivity for users of laptop computers, cellular phones, and other mobile devices. Already, Clearwire offers wireless broadband services to nearly 200,000 subscribers in 34 U.S. markets and in two European markets. The technology currently used by Clearwire, however, is viewed as a precursor to WiMax. Over its four-year existence, Clearwire has also reported losses of nearly $460 million and has confirmed plans to spend $4 billion through 2013 on the construction of its WiMax network. Although Clearwire shares sold at $25 each, or near the top of the company’s IPO price range, on the opening day of trading last Thursday, prices fell by 11% the next day and sunk another 3% by the closing bell on Monday.