Starbucks Corporation shares have lagged the S&P 500 in 2021, generating a year-to-date total return of 8.9 percent. At this point, investors may be wondering whether Starbucks shares are undervalued after their recent performance. Earnings A price-to-earnings ratio (PE) is one of the most basic fundamental metrics for gauging a stock’s value. The lower the PE, the higher the value. For comparison, the S&P 500’s PE is at about 29.4, nearly double its long-term average of 15.9. Starbucks’ PE is 37.7, well above the S&P 500 average as a whole. Starbucks’ PE ratio is also up 11.8 percent over the past five years, suggesting the stock is priced at the high end of its historical valuation range. Growth Looking ahead to the next four quarters, the S&P 500’s forward PE ratio looks much more reasonable at just 21.6. Starbucks’s forward earnings multiple of 33.4 is still more than 50 percent …