This thesis evaluates the neutrality of the Norwegian Petroleum Tax Act (PTA) in light of theories on neutral taxation by Boadway & Bruce (1984), Fane (1987) and Sandmo (1989). More specific, we investigate if there is neutral fiscal treatment of equity based capital investments in the onshore and offshore tax regimes and furthermore if decisions offshore are affected by tax position. Relevant research is presented and applied in a descriptive analysis of the current fiscal system offshore to reveal systemic distortive properties. Our analysis show that companies in theory should be indifferent to the distribution of tax allowances. Furthermore, we find that the petroleum tax act is not in accordance with theory regarding how normal returns...