David Tepper-led hedge fund Appaloosa Managemen sued to prevent SunEdison's yieldco from taking over some of Vivint Solar's assets after SunEdison acquires the rooftop panel installer.
The yieldco, TerraForm Power, is to acquire Vivint's residential solar rooftop portfolio after SunEdison completes the Vivint transaction.
Appaloosa is seeking "immediate injunctive relief", given that SunEdison's acquisition of Vivint could close "at any time," the hedge fund said in a filing in a Delaware court on Tuesday.
SunEdison shares fell about 10 percent in morning trading, while TerraForm Power's shares rose about 2 percent.
Appaloosa has repeatedly said the acquisition of Vivint's assets by TerraForm Power was not in the interest of the yieldco's shareholders.
Funds affiliated with Appaloosa together owned 9.5 percent of the outstanding class A shares of TerraForm Power as of December.
Appaloosa demanded to inspect TerraForm Power's books to learn more about its dealings with SunEdison, a request that the yieldco rejected in December.
"Although Appaloosa served a revised demand and was attempting in good faith to resolve the company's objections, it has thus far been unable to do so," Appaloosa said.
SunEdison, which agreed to buy Vivint Solar in July, said in December that TerraForm would pay about $799 million for Vivint's portfolio, lower than the initial purchase price of $922 million.