By Dan Weil Bank of America strategists offered a list of S&P; 500 stocks with the highest five-year price betas, a measure of volatility. The concept of beta – which measures a stock’s volatility compared with the market as a whole – is an important one for equities. So is the concept of equity-risk premium — that’s how much more return you should get if you invest in stocks instead of risk-free assets like Treasury securities. The equity-risk premium has soared 42% this year. How do the two concepts relate to each other? “In a rising equity-risk-premium environment, stocks with the highest …