CoStar Group’s President and CEO, Andrew C. Florance, bought 68,330 shares in the open market on May 1, 2026, spending about $2.40 million at $35.17 per share. Open-market buys are often watched closely because they involve an executive using personal funds to increase their stake, rather than receiving shares through pay programs. Florance’s role matters because a CEO typically has the broadest view of company performance, strategy, and competitive positioning. While any single trade should be weighed alongside fundamentals and valuation, a purchase of this size is a clear, voluntary increase in ownership by the top executive. Over the past 30 days, this was the only reported insider transaction at CSGP. The note about March 2026 activity suggests other executives’ recent transactions were mainly non-open-market items such as stock awards, which are common and usually scheduled as part of compensation plans. Against that backdrop, Florance’s open-market purchase stands out as the most meaningful recent insider signal in terms of discretionary buying.