PurposeThis study aims to investigate the nature and degree of US economic policy uncertainty spillover on the stock markets of a group of non-conventional economies like the Gulf Cooperation Council (GCC) countries, where a risk-sharing-based financial system is prominent and foreign investment, risk-free interest, derivatives, etc. are not as widespread as in the western economies.Design/methodology/approachthe monthly data of 1992–2018, linear and nonlinear structural vector autoregression (VAR) model, and an impulse response-based test to explore the nature and degree of US economic policy uncertainty spillover on the stock markets of the GCC countries.FindingsThis study finds that an unexpected increase in the US economic policy uncertainty significantly decreases the stock market index of all the GCC countries. This study also gets this relationship symmetric, meaning that the GCC stock market indices decrease and increase by the same amount when the US economic policy uncertainty increases and decreases, respectively.Originality/valueThis study investigates the characteristics of economic policy uncertainty spillover from the biggest economy of the world to the stock markets of the GCC region, which is new to the literature. The study results provide the first evidence that a risk-sharing based financial system does not necessarily protect the stock market from US uncertainty shock. However, the abundance of local investors, risk-sharing investment activities, the absence of derivatives, etc. may be responsible for the symmetric behavior of a stock market.