Is CoStar Group, Inc. overvalued or undervalued?

As of 24 October 2025, the valuation grade for CoStar Group, Inc. has moved from fair to attractive, indicating a more favorable assessment. The company appears to be overvalued, primarily reflected in its high P/E ratio of 283, significantly above the industry average, and an EV to EBITDA ratio of 202.31, which suggests that investors are paying a premium for earnings before interest, taxes, depreciation, and amortization. Additionally, the Price to Book Value stands at 3.87, further supporting the notion of overvaluation.
In comparison to its peers, CoStar Group's P/E ratio is notably higher than VeriSign, Inc. at 33.05 and Check Point Software Technologies Ltd. at 53.34, both of which are in the same industry. Furthermore, the company has underperformed against the S&P 500 over various time frames, with a 3-year return of 9.10% compared to the S&P 500's 78.85%, reinforcing the view that it may be overvalued relative to its growth prospects.