Question: How is the range of beta values defined for a portfolio of risky assets? Multiple select question. The lowest possible portfolio beta is defined as the beta of a risk-free asset, or zero. The highest portfolio beta is defined as the beta of the overall market, or 1.0. The lowest possible portfolio beta is defined as the lowest beta of any security held in the portfolio. The highest possible portfolio beta is defined as the highest beta of any security held in the portfolio.