Can risk-free and zero-beta portfolios be constructed? UK and US Evidence

This paper determines whether a risk-free portfolio can be formed using gold, T-bills, silver, platinum, and palladium. We construct zero-variance portfolios composed of two assets showing that it is possible to construct risk-free portfolios based on zero variance. We apply Wald tests to Black's zero-beta CAPM to examine whether these constructed risk-free portfolios qualify as zero-beta portfolios. We find that a risk-free portfolio is not always a zero-beta portfolio. Results show that a risk-free portfolio and a zero-beta portfolio in one market is not necessarily so in another.