What share for gold? On the interaction of gold and foreign exchange reserve returns

Almost five decades after the collapse of the Bretton Woods system, gold continues to form an important share of global foreign exchange reserves. This may be because gold has traditionally offered reserve managers many benefits, such as the absence of default risk. This paper explores whether these large investment shares in gold are also justified from a risk-return standpoint, or whether any other explanations have to be brought to bear. To do this, we go beyond the simple application of portfolio optimisation techniques, comprehensively analysing all possible long-only combinations of gold and representative fixed income reserve portfolios. We conclude that the market risk associated with gold is substantial when evaluated against a broad range of criteria, such as mitigating portfolio volatility, tail-risk, the probability of loss, and measures of diversification. This will tend to limit overall allocations. Nonetheless, for portfolios with higher sensitivity to interest rates (duration) and for reserve managers who measure their returns in a non-reserve currency, we find evidence that gold may function as a hedge, making it easier to justify sizeable gold holdings from a purely quantitative perspective.