The Norwegian state-owned Petroleum Fund's market value is more than one trillion US dollars, and the Norwegian state has become one of the world's largest stockowners. The Fund was established in 1990 and in 2006 and renamed the ‘Government Pension Fund Global’, as savings for future generations. What kind of values form the basis for describing the Petroleum Fund in this way? This article shows that the idea that present generations should not empty the North Sea of oil and gas (...) without saving something for future generations has been stable since the 1970s. However, over time, the understanding of how to save has changed. More specifically experts, bureaucrats and politicians have shifted their arguments during four phases: moderation in oil extraction (1974–1983); introduction of the national wealth model (1984–1990); a financial fund for the present and the future (1991–2006); and increased income and new protests (2007–2019). These four periods show that over time the idea of weak sustainability and value commensurability have increasingly come to dominate the argumentation in public documents about the Petroleum Fund. (shrink)