Key Takeaways BP (BP) American depositary receipts (ADRs) fell in premarket trading Tuesday after the energy giant said that it expects lower refining margins and an impairment charge of up to 2billionwillimpactitssecond−quarterresults.BPJoinsExxoninWarningAboutRefiningMarginsExxonMobil(XOM)onMondaysaidthatlowerrefiningmarginswouldcauseitssecond−quarterprofitstobebetween1.1 billion to $1.5 billion lower. The company also expects lower natural gas prices to cause a hit of a ...