Wall Street's nightmare stock had a dream come true

SunEdison, the solar manufacturing company that has been the bane of Wall Street's existence since it started crashing in July, is having a wonderful day.

That's rare these days.

The stock surged 36% in Thursday's trading day.

The reason why SunEdison surged is related to the reason it plummeted in the first place - SunEdison's attempt to acquire residential solar company, Vivint.

From Bloomberg:

Vivint shareholders led by Blackstone Group LP., which owned 77 percent of the shares at the start of the year, approved the $1.9 billion deal Wednesday, with more than 100 million votes in favor and 101,000 against.

SunEdison's shares took a nosedive when the Vivint deal was announced in July, because its terms revealed to investors that SunEdison was likely not as cash rich as they assumed. Additionally, the deal included "take or pay agreements" with TerraForm Power, SunEdison's yieldco - a sister company SunEdison created to manage its projects like a utility.

The take or pay agreement, which forces TerraForm Power to purchase certain Vivint assets, upset TerraForm Power shareholder, hedge fund manager David Tepper of Appaloosa Management. He doesn't think those assets are actually as valuable as SunEdison is making them out to be, so he's suing SunEdison over the deal.

And while SunEdison had a monster Thursday, it's still down 92% over the last year.

So this ain't over yet, people.