CoStar Shorts Rebound After Q3 Results

CoStar Group reported third-quarter earnings on October 27 and fell 5% on the day. Short sellers moved quickly: positions have climbed 15.6% over the past week to 15.3 million shares, or 3.6% of the free float.

That weekly build is notable in context. The pre-report note from October 24 described a short base that had shrunk 30% over the prior month, from roughly 18.9 million shares in mid-September to around 13 million, as the stock rallied 18% into the print. That covering trade is now being partially reversed. Shares short rose from 13.0 million on October 23 to 15.3 million on October 27, the largest two-day addition in at least six weeks. The borrow market has tightened alongside it. Availability has dropped from roughly 4,360% on October 23 to 2,969% now, still very loose by any standard, meaning there are far more shares available to borrow than there are shares currently lent out. Borrowing costs remain negligible at 0.44%, down about 20% on the week. There is no stress in the lending market; new shorts are cheap and easy to initiate, which is precisely what the data shows them doing.

Options positioning offers little drama to set against the short rebuild. The put/call ratio has drifted slightly below its 20-day average, registering 0.558 against a mean of 0.567, a z-score of -0.41. That is well within normal range and does not point to any unusual demand for either protection or upside exposure. The 52-week range for the PCR runs from 0.19 to 0.78, and the current reading sits roughly in the middle, suggesting that options traders have not meaningfully repositioned in either direction around the print.

The Street came into this week divided and remains so. A cluster of analysts cut targets and ratings after the July 28 quarter: Citigroup dropped coverage to Neutral from Buy, William Blair moved to Market Perform, and Keefe Bruyette lowered to Market Perform while cutting its target to $29. Those who stayed constructive, JPMorgan at Overweight with a $52 target, BTIG at Buy with $42, and Needham at Buy with $40, still imply meaningful upside from the $32 level, and the consensus mean target is $36.15. Against a closing price of $32.01, that gap is real but narrow relative to the debate. The bull case rests on subscription durability, 95% renewal rates in the core commercial platform, and the path to margin expansion as Homes.com investment plateaus. The bear case points to over $3 billion already spent on the residential strategy, a GAAP EPS base of $0.61 expected in 2026, and the risk that cyclical commercial real estate weakness slows bookings before the margin story materialises. On valuation, the P/E now runs at 18.8x, up roughly 2.6 turns over the past 30 days despite the stock falling on the day, suggesting the earnings base has moved more than the price. EV/EBITDA has compressed slightly to 12.6x. Forward EPS momentum scores well, ranking in the 96th percentile for 12-month forward year-on-year increase, but the EV/EBIT factor ranks in the 2nd percentile, reflecting how expensive the business looks on operating earnings.

The one piece of genuinely differentiated insider data from October remains relevant here. CEO Andrew Florance bought 83,300 shares at $29.89 on August 4 for roughly $2.49 million, an open-market purchase with no 10b5-1 plan attached. That trade was made at prices below the current level and represented a meaningful personal commitment. Against it, the CFO and Chief Accounting Officer recorded smaller tax-withholding transactions in the weeks around it, which are compensation mechanics rather than conviction trades. The net insider position over the past 90 days is positive at roughly $2.24 million and 75,000 shares, almost entirely attributable to the CEO purchase. Wikipedia page views for the company are running at a z-score of 2.5 against the prior 90-day average, consistent with elevated retail attention following the earnings release.

Retail attention has spiked, the CEO is long from below current levels, and fresh short interest has rebuilt quickly since the print. The next scheduled earnings date is February 16, 2027, leaving 111 days for the data on Homes.com traction and commercial bookings to either corroborate or challenge the positions taken this week.