Key Takeaways
- CoStar Group’s revenue growth decelerated for a second straight quarter, from 26.89% year over year in Q4 2025 to 22.54% in Q1 2026 to 18.44% in Q2 2026, with Q1 revenue even dipping slightly below Q4 on a sequential basis.
- Management cut full year 2026 revenue guidance while raising adjusted EBITDA guidance by $30 million at the midpoint, framing the slowdown as a deliberate trade of growth for margin.
- Quarterly GAAP EBITDA swung from a low of $18.1 million to a high of $161 million over the past eight quarters, with year over year changes ranging from negative 69% to positive 332%, far more volatile than the smooth adjusted EBITDA figures management highlighted on the call.
- Net new bookings fell about 26% year over year in Q2, the specific number five separate analysts pressed management on, and it ties directly to the growth deceleration playing out in the revenue trend.
CoStar Group’s Growth Deceleration Predates Its Q2 Explanations
CoStar Group (CSGP) posted 18% revenue growth in Q2 2026, its 61st straight quarter of double digit growth. On its own, that sounds fine. But the trend underneath it is not flat, it is decelerating, and it started before the quarter management spent an hour explaining.
Quarterly revenue growth peaked at 26.89% year over year in Q4 2025, then slipped to 22.54% in Q1 2026, then to 18.44% in Q2 2026. That is two consecutive quarters of deceleration, not one. Revenue in Q1 2026 ($897.0 million) was even slightly below Q4 2025 ($899.9 million), an unusual sequential dip for a company that has compounded growth for 15 years.
Management’s Q2 call attributed the lowered full year guide to three specific actions: restructuring Ten-X, cutting Homes.com’s inside sales force from 660 reps to about 400, and holding Apartments.com pricing against a competitor discounting for share. Those are real, quantifiable choices. But the deceleration trend began at least a quarter before CFO Christian Lown detailed them, which raises a fair question for CSGP stock: how much of the slowdown is strategic discipline, and how much is discipline dressed up to explain softness that was already showing.
CSGP Stock’s Adjusted EBITDA Story Looks Smoother Than the Raw Numbers
The profitability side of the story is the more polished one. Management said Q2 adjusted EBITDA reached $184 million, more than doubling year over year, with margin expanding 900 basis points to 20%. Adjusted EBITDA guidance for the full year was raised $30 million at the midpoint to $780 million to $820 million, and adjusted EPS guidance rose 6% from the February range.
The raw GAAP EBITDA numbers tell a rougher story. Over the same eight quarters, GAAP EBITDA moved from $59.2 million to $79.7 million to $22.0 million to $39.0 million to $18.1 million to $130.5 million to $85.0 million to $161.0 million. Year over year swings ranged from negative 33% to positive 332%, with a stretch of negative 69% in between. That is not a smooth margin expansion story, it is a company whose reported profitability jumps around sharply before adjustments smooth it into the narrative investors hear on the call.
Large gaps between GAAP and adjusted profitability are not automatically a red flag, especially for a company absorbing restructuring costs at Ten-X and Homes.com plus integration costs from Matterport and the pending Zonda deal. But the size of the gap here means investors are being asked to trust the adjustments more than usual, and that trust is doing real work in the bull case for CSGP stock.
Where CoStar’s Slower Growth Is Actually Coming From
The three businesses management named account for most of the gap. Ten-X revenue declined $4 million year to date during its restructuring, representing about a quarter of the full year guidance cut. Homes.com cut its inside sales headcount by nearly 40% while shifting toward a smaller, more experienced field team in five metros, a move management says lifted productivity per rep by 19% even as total net new bookings held roughly flat quarter over quarter. Apartments.com chose not to match a rival’s aggressive discounting, holding average revenue per property largely flat while conceding some new client volume to a lower price point.
Each of these is defensible in isolation. Together, they explain why net new bookings fell 26% year over year even as CoStar’s core commercial platform, CoStar Suite, grew subscribers 19% and residential posted its first quarterly segment profit since Homes.com launched in 2024.
Is CoStar’s Margin First Pivot the Right Call for the Stock?
The evidence supports a specific, narrower conclusion than either the bull or bear framing offers on its own. CoStar’s core CoStar Suite and LoopNet businesses are genuinely accelerating, with subscriber growth and renewal rates that do not look like a company in trouble. The deceleration is concentrated in exactly the three areas management said it would slow down deliberately, which is consistent with their explanation rather than contradicting it.
The risk is that the adjusted EBITDA narrative is carrying more weight than the GAAP numbers would support on their own, at a moment when the company is also absorbing an $800 million acquisition and a CFO transition. The next two quarters of net new bookings, not revenue growth alone, will show whether the field sales pivot at Homes.com and the pricing discipline at Apartments.com actually reaccelerate demand or simply preserved margin while ceding ground.
Should You Invest in CoStar Group, Inc.?
The only way to really know is to look at the numbers yourself. TIKR gives you free access to the same institutional-quality financial data that professional analysts use to answer exactly that question.
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Disclaimer:
Please note that the articles on TIKR are not intended to serve as investment or financial advice from TIKR or our content team, nor are they recommendations to buy or sell any stocks. We create our content based on TIKR Terminal’s investment data and analysts’ estimates. Our analysis might not include recent company news or important updates. TIKR has no position in any stocks mentioned. Thank you for reading, and happy investing!
