In September 2015, NNPC announced that it intends to review deepwater PSCs, in a move which took some in the industry by surprise. Its primary aim is to increase its fiscal take from producing deepwater fields which have provided lucrative returns for those IOCs who bore the risks of exploration and development in a frontier location. These assets are not yet half way through their life-spans with 3.3 billion barrels of oil still to be produced and US$35 billion of contractor value remaining. The stakes are very high, and so re-negotiation will be difficult and is likely to last years. We assess which IOCs are most exposed to tougher fiscal terms.