Tesla’s CEO, Elon Musk, is at the center of a new court battle seeking to determine if he had undue influence to force the automaker to buy SolarCity, a solar panel maker, in 2016.

At the heart of the case, which starts Monday, is the question of whether or not Elon Musk, despite owning just 22% of Tesla, wields enough influence to control Tesla to make decisions that do not benefit the company, according to Reuters.

Shareholders allege that Musk used his control over the company to drive a deal to rescue SolarCity from bankruptcy in 2016. The investors are suspicious of the deal because it saved Musk’s own investment in the company that was founded by two of his cousins. Plaintiffs also allege that Musk pushed Tesla’s board to negotiate against itself and raise (not lower) the price it was offering for SolarCity.

Read More: Tesla Hit With Shareholder Lawsuits After SolarCity Buyout

Although Musk was the largest stakeholder in SolarCity, four other Tesla board members also owned SolarCity stock, according to court records. Those board members settled the allegations against them last year for $60 million but they did not admit fault.

Musk says, though, that he was “fully recused” from board negotiations and shareholders voted to approve the deal because it was a part of his master plan for the company. He argues, that the sale was actually just evidence of his strong management.

With just 22% of Tesla, Musk may not appear to own a controlling share of the company but, according to Ann Lipton a professor at Tulane Unversity Law School who spoke to Reuters, it will be hard for the court to ignore Musk’s celebrity status and his relationship with Tesla.

“Put it all together, and it might be enough to count as a controlling shareholder,” she said.

Starting on Monday, the trial will last two weeks in the Court of Chancery in Wilmington, Delaware. Plaintiffs are looking for Musk to repay to Tesla the cost of the $2.6 billion deal and to disgorge the profits on his SolarCity stock.