CoStar Q3 beats on profitability but key Residential spend details remain undisclosed

What happened

CoStar Group reported Q3 2026 revenue of $952 million, up 14% year-over-year, with net income swinging to a positive $74 million from a prior-year loss. Adjusted EBITDA surged to $229 million, doubling year-over-year and prompting management to raise full-year 2026 Adjusted EBITDA guidance. The press release highlights record revenue and profitability, but omits segment-level details, particularly Residential marketing spend and Residential Adjusted EBITDA, which were the central focus of the prior investment thesis. Net new bookings of $37 million were disclosed, but the announcement lacks the granularity needed to confirm whether Homes.com's marketing stepped down from the Q1 level of $209 million as required by the board-approved glidepath. While the headline numbers are encouraging, investors must await the 10-Q filing to verify that the improvement is driven by sustainable operating leverage rather than one-time items or cost shifting.

Implication

For investors, the Q3 release provides a positive catalyst but not yet a definitive answer to the key question of whether Homes.com is transitioning to a more efficient growth model. The raised Adjusted EBITDA guidance suggests management expects continued profitability improvement, but the market's reaction will likely hinge on the segment data in the forthcoming 10-Q. If the filing shows Residential marketing declined sequentially from $209 million and Residential Adjusted EBITDA loss narrowed further from the Q1 level of -$29 million, the base-case scenario (implied value ~$38) gains credibility and the stock could re-rate toward that level. Conversely, if marketing stayed elevated or losses widened, the bear scenario (~$24) would become more likely, and the current positive sentiment could reverse. Until those details are available, the prudent stance remains WAIT, with a bias to upgrade if the segment evidence confirms spend discipline without sacrificing growth.

Thesis delta

The Q3 headline results are incrementally positive, showing strong revenue growth and a dramatic swing to profitability, which reduces near-term financial risk. However, the thesis is not yet de-risked because the press release does not disclose the Residential segment marketing spend or Adjusted EBITDA, which were the critical proof points for the board-approved investment glidepath. A shift in probability toward the base case (and away from bear) would require the 10-Q to show Residential marketing below $190 million quarterly and Residential Adjusted EBITDA loss improving to around -$30 million or better; without that, the WAIT rating remains appropriate.