Is Calumet Specialty Products Partners LP overvalued or undervalued?

As of 5 March 2020, the valuation grade for Calumet Specialty Products Partners LP has moved from fair to risky, indicating a significant deterioration in its financial health. The company is currently overvalued, as evidenced by its negative P/E ratio and a Price to Book Value of -1.34. Additionally, the EV to EBITDA ratio stands at an alarming 64.40, suggesting that the market is pricing the company excessively high relative to its earnings potential.
In comparison to its peers, Calumet's valuation metrics are concerning; for instance, Star Group LP, which is rated very attractive, has a P/E of 5.97 and an EV to EBITDA of 4.38. This stark contrast highlights the overvaluation of Calumet, especially given its negative return on capital employed (ROCE) of -9.63%. While Calumet has shown a strong performance over the long term with a 5-year return of 509.62%, its recent YTD decline of -28.02% compared to the S&P 500's 2.44% underscores the risks associated with its current valuation.