Is McKesson Corp. overvalued or undervalued?

As of 2 February 2021, the valuation grade for McKesson Corp. moved from attractive to risky, indicating a shift in its perceived investment quality. The company appears to be overvalued, given its high P/E ratio of 56 and an EV to EBITDA ratio of 36.93, which significantly exceeds those of its peers. For comparison, Boston Scientific Corp. has a P/E of 73.71 and an EV to EBITDA of 45.38, while Cencora, Inc. shows a more reasonable P/E of 40.09 and an EV to EBITDA of 19.45.
Despite the overvaluation, McKesson has demonstrated strong stock performance, with a 1-year return of 34.89% compared to the S&P 500's 17.14%, and a remarkable 5-year return of 353.64% against the S&P 500's 96.61%. However, the negative price-to-book value of -84.94 and the negative return on equity suggest underlying financial challenges that could impact future performance.