ExxonMobil said Friday that higher refining margins added substantially to its third-quarter earnings even as changes in oil prices took a toll on the supermajor's upstream segment by more than $1 billion.

The company, in a regulatory filing Friday, said changes in refining margins added $4.5 billion to its third-quarter earnings on top of the $4.1 billion from the second quarter.

ExxonMobil, however, warned that "changes" in oil prices lowered its third-quarter upstream earnings by $1.3 billion from the second quarter.

Exxon posted earnings of $7.9 billion in its upstream segment in the second quarter. The energy giant posted an upstream profit of $7.5 billion during the third quarter last year.

ExxonMobil stock rose 0.9% to $176.18 in premarket trading on Friday after ending Thursday down 1.3%. Shares have risen 45% this year and closed at a record high of $177.01 on Wednesday.

The stock has been enjoying the benefits of increased oil prices as the conflict between the U.S. and Iran has kept Brent and West Texas Intermediate oil prices elevated.

Along with Exxon, Chevron rose 0.6% to $220.65 before the opening bell.

ExxonMobil is expected to report official third-quarter earnings later this month.