Shares of CoStar fell 5.8% following Q1 2026 earnings, as investor reactions focused on a more cautious tone in the company’s outlook and ongoing investment intensity, with the transcript lacking clear upward revisions to guidance or visibility on margin expansion despite top-line growth.

• Q1 2026 revenue grew 23% year-over-year, with adjusted EBITDA doubling to $132 million—26% above the midpoint of previous guidance.
• Net new bookings reached $67 million (up 20% YoY), with notable momentum in commercial products, CoStar core, and debt solutions.
• Management emphasized substantial ongoing investment, particularly in Homes.com and new product launches; no specific upward guidance revision was provided during the call.
• Segment highlights included 15% YoY revenue growth and $161 million EBITDA in commercial, and strong acceleration in international regions (e.g., UK revenue up 25%, net new bookings up 44%).
• Despite operational positives, the lack of a more optimistic forward outlook or increased margin targets appeared to disappoint investors, driving the post-earnings stock decline.