Jan. 10 (Bloomberg) -- Solar-energy companies climbed today after LDK Solar Co. raised its guidance and Edison International announced several power-purchase agreements in California.

LDK, a Xinyu, China-based maker of solar products, climbed 19 percent to $12.39 at 1:22 p.m. in New York Stock Exchange composite trading, the largest percentage gain in two months. The company said today fourth-quarter sales will be 21 percent higher than the top end of its previous $750 million estimate.

Edison said its Southern California Edison utility will buy energy from three solar farms that SunPower Corp. plans to build in the state, with total capacity of 711 megawatts. The unit also said it had signed four contracts to purchase power from plants being developed in California by Fotowatio Renewable Ventures Inc., with a combined capacity of 120 megawatts.

SunPower increased 7.5 percent to $14.45, the biggest gain of any company in the 100-member WilderHill New Energy Global Innovation Index. Six of the 10 companies on the index with the biggest percentage gains today make solar products.

“The space has tended to move as a whole,” Adam Krop, an analyst with New York-based Ardour Capital Partners said, in an interview. Several solar energy companies were riding the coattails of LDK and SunPower, he said.

Shanghai, China-based JA Solar Holdings Co. increased 4 percent to $7.41 while Suntech Power Holdings Co., a Jiangsu, China-based solar cell maker, was also 4 percent higher.

“The space has been really undervalued for the past four to six weeks,” Krop said. “With all these positive news announcements, eventually there has to be some positive movement.”

Trina Solar Ltd. of Changzhou, China, increased 2 percent to $25.53. First Solar Inc., the biggest U.S. solar company, advanced 2 percent as well to $136.20. Apollo Solar Energy Technology Holdings Ltd. of Hong Kong rose 1.8 percent.

LDK Solar is not part of the WilderHill index.

--Editors: Randall Hackley, Will Kennedy

To contact the reporter for this story: Will Wade in New York at wwade4@bloomberg.net

To contact the editor responsible for this story: Reed Landberg at landberg@bloomberg.net.