Is CoStar Group, Inc. overvalued or undervalued?

As of 21 November 2025, the valuation grade for CoStar Group, Inc. moved from attractive to fair, indicating a shift in its perceived value. The company appears to be overvalued, particularly given its high P/E ratio of 283 and an EV to EBITDA of 202.31, which are significantly above industry norms. Additionally, the Price to Book Value stands at 3.87, further suggesting that the stock may not be justified at its current price.
In comparison to peers, CoStar Group's P/E ratio is markedly higher than VeriSign, Inc. at 33.05 and Check Point Software Technologies Ltd. at 53.34, which indicates a premium that may not be warranted. Furthermore, the company's recent stock performance has lagged behind the S&P 500, with a year-to-date return of -6.06% compared to the S&P 500's 12.26%. This underperformance reinforces the notion that CoStar Group may be overvalued in the current market environment.