Carnival Corp. shares have lagged the S&P 500 in 2021, generating a year-to-date total return loss of 5.1 percent. Carnival stock has had a wild ride since the 2020 shutdowns, but investors may be wondering whether there’s any value in Carnival shares after its 2021 pullback. 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 28.7, nearly double its long-term average of 15.9. Carnival doesn’t currently have a PE ratio because the company is not profitable. In the most recent quarter, Carnival reported a $2-billion net loss. Growth Looking ahead to the next four quarters, the S&P 500’s forward PE ratio looks much more reasonable at just 20.8. Unfortunately, analysts are not expecting Carnival to turn a profit over the next four quarters. The …