CoStar Group reported Q1 2026 revenue of $897M (+23% YoY), Adjusted EBITDA of $132M (+100% YoY, 26% above guidance midpoint), and raised FY2026 EBITDA guidance by $30M at midpoint to $780-820M. The print extended a 60-quarter streak of double-digit growth and compressed residential segment losses by $56M YoY. Yet CSGP closed at $35.96 on earnings day, down ~16% from $42.93 at the prior assessment. Six of seven prior key uncertainties trended favorably; the seventh — why the stock is moving against the operational thesis — is now the dominant question. Thesis classification shifts price-at-value to price-below-value with MEDIUM confidence.
The Numbers
Both Engines Firing
Q1 was the first quarter in some time where both segments contributed unambiguously positive evidence to the thesis:
- Commercial RE +15% YoY ($472M): CoStar Suite (with Information Services) +9%, LoopNet accelerated to +16%, Other Commercial RE (Matterport, 10-X, BizBuySell) surged +81%. Adjusted EBITDA expanded $151M → $161M.
- Residential RE +32% YoY ($425M): Adjusted EBITDA loss compressed from $(85)M to $(29)M — a $56M improvement that puts management's 5-7% Residential Adj EBITDA margin target for FY2026 on credible footing.
- Homes.com members 35,000 (+200% YoY): Up from ~31K at year-end. The February 2026 launch of Homes AI drove a 119% YoY organic traffic increase with engagement metrics described as "best-ever time on site, page views, and bounce rates."
- Net new bookings $67M (+20% YoY): Company-wide; Homes.com-specific contribution not disclosed.
Capital Allocation Pivots to Buybacks
The Q1 capital deployment pattern is a notable break from the acquisition-led 2024-2025 cycle. Zero new M&A in Q1 2026 (versus the $750M Matterport closing in prior-year Q1). Instead, $505M deployed to share repurchases via accelerated share repurchase — most of the announced FY2026 $700M buyback plan executed in a single quarter.
Buying back stock at $35-42 implies management views current valuations as attractive. The cost: cash declined to $1.215B from $1.633B at year-end (total $1.316B with restricted), still well above the $1B trigger but the pace deserves monitoring. The Stress Scanner FUNDING_FRAGILITY signal stays STABLE but with tighter bounds.
Forecast Markets: Revenue Beat Resolved YES
| Market | Prior | After Q1 | Driver |
|---|---|---|---|
| Q1 2026 revenue beats consensus | 0.70 | RESOLVED YES | $897M beat midpoint; Brier 0.09 (green) |
| Homes.com $100M FY2026 organic | 0.22 | ~0.45-0.55 | 35K members ≈ $100M+ run rate; threshold may be cleared |
| CRE volume above pre-pandemic H1 | 0.30 | ~0.45-0.55 | Other Commercial RE +81% YoY; LoopNet +16% |
| Domain EBITDA margin below 30% | 0.30 | ~0.20-0.25 | Residential losses cut 66%; no integration distress |
| Apartments growth below 10% by Q2 | 0.18 | ~0.18 | Apartments-specific revenue not broken out; segment +32% |
| Homes bookings $6M monthly by Q2 | 0.12 | ~0.15 | Bookings not split out; high bar even with traffic gains |
| Cash below $1B by FY2026 end | 0.19 | ~0.22 | Q1 burn $418M; $200M open-market repo remaining |
| Zillow ruling favorable to CSGP | 0.16 | ~0.16 | No litigation update in Q1 8-K |
The Q1 revenue-beat resolution is a calibration win: the 0.70 prior probability proved well-anchored on CoStar's subscription model and management's systematic guidance conservatism. Brier score 0.09 lands in the green band. The directional updates on Homes.com revenue and CRE volume reflect Q1 evidence that pulled probabilities meaningfully toward YES.
Four Signals Moved Across Four Lenses
- Gravy Gauge — REVENUE_DURABILITY: CONDITIONAL trending toward DURABLE. Both segments contributed to the revenue beat. The 60-quarter streak with multiple growth engines firing simultaneously strengthens the durability case.
- Myth Meter — NARRATIVE_REALITY_GAP: DIVERGING narrowing toward CONVERGING. Homes AI traction (119% organic traffic, 35K members) is the strongest operational evidence yet that the residential narrative has economic substance.
- Stress Scanner — FUNDING_FRAGILITY: STABLE (slightly tighter). Cash $1.316B (down from $1.733B at year-end) after $505M Q1 buyback; still well above thresholds but pace deserves monitoring.
- Consolidation Calibrator — CAPITAL_DEPLOYMENT: AGGRESSIVE (improving). No new M&A in Q1; deployment pivoted to buybacks. Domain integration appears on track per residential loss compression.
Next Catalysts
- Q2 2026 earnings (late July) — primary test of residential profitability trajectory; potential Homes.com-specific revenue disclosure
- Q2 buyback disclosure — incremental authorization vs pause will signal both confidence and valuation discipline
- Homes AI engagement durability — track whether retention and conversion follow the 119% traffic gain and 4x-7x engagement uplift on AI-mode users
- Apartments.com revenue disclosure — Q4 2025 grew 11%; Q2 will reveal whether momentum holds above the 10% threshold
- Zillow litigation milestones — no Q1 update; accrual flat at $99M
See the full seven-lens CSGP analysis
The March 2026 CSGP deep-dive with the Gravy Gauge, Moat Mapper, Myth Meter, Stress Scanner, Fugazi Filter, Consolidation Calibrator, and Insider Investigator outputs, plus the eight forecast markets tracking the thesis.
Public Sources Used
- CSGP Q1 2026 Form 8-K (SEC EDGAR, filed 2026-04-28; Items 2.02 + 7.01 + 9.01): SEC EDGAR
- CSGP Q1 2026 earnings release Exhibit 99.1 (Andy Florance, Chairman/CEO; Christian Lown, CFO)
- CSGP Q4 2025 earnings transcript (baseline reference)
- CSGP FY2025 10-K (baseline analysis reference)
- Yahoo Finance (CSGP price as of 2026-04-28: $35.96)