Pfizer Inc. shares have lagged the S&P 500 in 2021, generating a year-to-date total return of 16.6 percent. Pfizer has gotten plenty of headlines for its COVID-19 vaccine, but investors may be wondering just how much value is left in the pharma giant’s stock? 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 currently at about 34, more than double its long-term average of 15.9. Pfizer’s PE is currently 19, significantly below the S&P 500 average as a whole. Pfizer’s PE ratio is down 41.7 percent over the past five years, suggesting the stock is currently priced at the low 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 …