BP’s assets have been valued at $1.075bn, while the market value of inventory is calculated at $1.3bn, including $100m purchase price reduction for the clearance with regulatory authorities.

Tesoro president and CEO Greg Goff said with FTC’s approval, the company can now close the transformational acquisition as per plan.

"This transaction is a unique opportunity for Tesoro to combine the best aspects of two West Coast refining, marketing and logistics businesses resulting in a more efficient world-scale integrated refining, marketing and logistics system," Goff added.

Tesoro will build a Los Angeles refining complex by combining its existing Los Angeles refinery with the adjacent Carson refinery to result in annual synergies of about $250m with an additional capital investment of almost $225m.

The company is also planning to take advantage of the operational synergies through integrated supply of crude oil, improved utilization of intermediate feedstocks and product distribution costs, improvements in light product yield and reductions in manufacturing costs and stationary source air emissions.