portfolio as the combination of risky assets that minimizes standard deviation, and identifies it as the point where the efficient frontier begins.

When a risk-free asset is introduced, the efficient set is no longer limited to the upper portion of the Markowitz frontier. In that case, the relevant portfolio of risky assets is the tangency portfolio, which is the portfolio where the capital allocation line is tangent to the efficient frontier. The same source describes this portfolio as the optimal market portfolio in the standard