First Solar and SunPower Plan to Form Joint-Venture Yieldco

First Solar Inc. and SunPower Corp., the two largest U.S. solar-panel manufacturers, are planning a joint venture that will own and operate some of their projects. The companies expect to register for an initial public offering for the new venture, according to a statement Monday. They didn’t say when that may occur or how much they would seek to raise through the IPO. The shares surged in after-hours trading.