International reserves: Facing model uncertainty

•In this paper we search for the most important cross-country determinants of reserve holdings and evaluate their importance using Bayesian model averaging (BMA).•Aside from evaluating the traditional determinants we introduce new variables and search for alternatives.•Trade openness and the broad-money-to-GDP ratio are the key determinants with a positive link to the level of reserves, while financial development seems to lower the need for reserves.