Since the oil price drop in 2014, oil & gas companies have refocused their portfolios in search of cost competitiveness. As a result, more companies have become de-facto specialists for certain asset types or geographies (such as North American unconventionals, oil sands, integrated gas projects). Conversely, the energy transition is spurring some larger companies to diversify into low-carbon solutions. How will this dichotomy of specialization and diversification impact the design of future upstream portfolios? How will diversified players make their capital allocation decisions between quite different business segments? What impact will the energy transition have on each class of upstream players?