Warren Buffet recently sold his stake in COP . He owned it before the company split up and did very well for Berkshire. He then took a stake in XOM , the largest integrated oil company in the world . Many have suggested that the reason COP was abandoned and XOM was bought is because , integrated oil isn't as sensitive to the price of oil ar a pure oil producer is . For integrated , as oil rises , production becomes more profitable while midstream and downstream operations lag . Conversely , as oil falls , production becomes less profitable and midstream and downstrean (refining,wholesale and retail) make more money. But perhaps his stake is more perverse than that . If XOM were to pull a COP and split itself up , the monetary gain from such a split would be incredible . Maybe he's buying XOM to have another COP on his hands . We all saw the results of the COP spinoffs. Could it happen again?