Russo and Ruby both work as fund managers with AARK Capital. Russo manages an indexed share portfolio where as Ruby is the fund manager of an actively managed share portfolio. Over the last year the T-Bill rate was 3% and the market return was 13.5%. If Russo's portfolio beta is 0.99 and the portfolio averaged 15% rate of return last year and Ruby's portfolio has a beta of 1.4 and the portfolio averaged 18% rate of return last year, which manager was the superior stock selector last year?