KEY TAKEAWAYS BP stock is falling in premarket trading Tuesday after the British oil giant said it expects to book impairments of between $1.0 billion to $2.0 billion in the fourth quarter.BP also forecast "weaker" fourth-quarter refining margins.

BP said on Tuesday that lower refining margins would hurt its fourth-quarter profit by $100 million to $300 million and that it expects oil trading to be weak.

BP forecasts that weaker realized refining margins will dent the Q4 earnings by up to $300 million. Refinery turnaround activity is also set to have a higher impact for the fourth quarter compared to the third quarter.

British oil major BP said on Tuesday that it expects its fourth-quarter upstream production to be lower than the third quarter. The forecast is due to lower output in oil production and operations, and in gas and low carbon energy.