NEW YORK (AP) — Tesla will spend about $2.6 billion on solar panel maker SolarCity in an all-stock deal.

While electric car maker Tesla Motors Inc. has said that the transaction would create a one-stop shop for cleaner energy, some have questioned the motives behind the deal. Elon Musk is the chairman and biggest shareholder of both companies. And SolarCity is run by his cousin, Lyndon Rive.

SolarCity's stock slid more than 6 percent before the market opened Monday.

The buyout, announced Monday, gives SolarCity Corp. stockholders 0.110 Tesla common shares per SolarCity share, which puts the value of SolarCity stock at $25.37 per share. Tesla previously said it would offer $23.56 to $25.30 per SolarCity share.

Musk has cultivated the image of a maverick since he made his initial fortune as co-founder of online payment service, PayPal, which eBay bought for $1.5 billion in 2002. He is hailed as a visionary by admirers who applaud him for shaking up the auto industry with Tesla's sleek, electric vehicles and drawing up plans to send people to Mars on Space X's rockets. His detractors ridicule him as an unpredictable control freak.

Musk owns a 26 percent stake in Tesla, based in Palo Alto, California, and a 22.5 percent stake in SolarCity. His motivation to pair Tesla with the San Mateo, California, solar company primarily revolves around a battery system that stores solar energy in homes and businesses.

The deal may draw more attention to the financial position of both companies. Tesla has lost $1.2 billion in the past two years alone while SolarCity has suffered losses exceeding $1.1 billion during the same span. Analysts surveyed by FactSet are predicting a 416 million loss from Tesla this year while they believe SolarCity will lose $851 million.

Tesla anticipates $150 million in costs savings in the first full year after closing of any tie-up with SolarCity.

SolarCity has a 45-day "go-shop" period in which it can solicit alternative acquisition proposals. It will have to pay Tesla a $78.2 million termination fee unless it ends the deal with Tesla in order to enter an agreement with a third party that initially made an alternative offer before the "go-shop" period ended. In such an instance, SolarCity would pay a $26.1 million termination fee, according to a regulatory filing.

The deal is expected to close in the fourth quarter. It still needs the approval of a majority of "disinterested" shareholders of both companies, meaning Musk wouldn't have a say.

Tesla's stock rose slightly in premarket trading.