Tesla Motors Inc has acquired SolarCity Corp for $2.6 billion in an all-stock deal that Tesla CEO Elon Musk says will yield significant cost savings and improvements in manufacturing efficiency.

Musk serves as chairman of SolarCity and is the largest shareholder in both firms. The energy systems company was co-founded by his cousins, Lyndon and Peter Rive.

Under the terms of the agreement, Tesla will control 93.5 percent of the combined entity while SolarCity will hold the remaining 6.5 percent. The deal is expected to be ratified in the fourth quarter, pending a “go-shop” stipulation that allows SolarCity to consider alternative offers for a 45 day period.

In a blog posted on Monday, the two companies indicated that they would offer electric vehicles, solar energy systems and battery storage solutions, fulfilling a key objective of Musk’s recently updated “master plan.”