Umbrella clauses in bilateral investment treaties (BITs) can be named in various ways with differing scopes and effects depending on their texts. It is debatable whether a host state can be held liable based on an umbrella clause in a BIT if it breaches an investment commitment arising from the investment contract. There are two mainstream opinions in this debate: the restrictive and broad approaches. In our opinion, a case-specific approach should be adopted. In each case, the tribunal should act in conformity with the principle of competence-competence. During this analysis, the use of the general rule of interpretation (Art. 31) in the Vienna Convention on the Law of Treaties (VCLT) should be considered.