Energy stocks were declining pre-bell Monday as the Energy Select Sector SPDR Fund (XLE) was 0.4% lower recently.

The United States Oil Fund (USO) was 2.4% lower and the United States Natural Gas Fund (UNG) was down 2.9%.

Front-month US West Texas Intermediate crude oil was 2.7% lower at $65.53 per barrel at the New York Mercantile Exchange. Global benchmark North Sea Brent crude oil lost 2.3% to $68.05 per barrel, and natural gas futures were down 2.8% at $3.00 per 1 million British Thermal Units.

Kosmos Energy (KOS) shares were down nearly 3% after the company reported that it swung to a Q2 adjusted loss as revenue declined during the period.

BP (BP) shares were up nearly 2% after the company said it made a "significant" oil and gas discovery at the Bumerangue prospect offshore Brazil.

Kodiak Gas Services (KGS) will replace NV5 Global (NVEE) in the S&P SmallCap 600, effective Wednesday, S&P Dow Jones Indices said. Shares of Kodiak Gas Services were more than 7% higher premarket.