There has been a growing interest in the extent to which international investment law imposes an obligation on the state to compensate for losses arising from an armed conflict. This contribution explores the prevalence of war clauses that hold the state liable to pay compensation for war losses without the investor needing to prove fault. The contribution considers a recent case against Syria in which an investor was permitted to rely on such a war clause in another treaty through the most favoured nation (MFN) clause. The contribution finds that MFN clauses substantially increase the number of investors who can rely on unqualified extended war clauses. It considers unqualified extended war clauses and the extent to which other investors can rely on them through an MFN clause in Cameroon, Syria and Yemen. It then considers the role that the BRICS countries can play in bringing about the necessary reforms to unqualified extended war clauses. It argues that these reforms are urgently needed as these states emerging from armed conflict can scarcely afford to meet their people’s most essential developmental needs, let alone virtually unlimited liability to foreign investors.