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Costar Group stock timeline
A year of the price with every insider trade, planned sale, earnings report and material 8-K marked
252 sessions−54.6% to $30.55
Costar Group (CSGP) stock fell 55% over the last 252 sessions, to $30.55. On the way it reported 0 quarters, its insiders filed 3 open-market trades and 1 Form 144 notice of planned sales, and the company filed 7 material 8-Ks. Each is marked on the price and listed with what the stock did next.
Each mark, and what followed
| Date | Kind | What | Next session | 5 sessions | 21 sessions |
|---|---|---|---|---|---|
| Oct 27, 2026 | 8-K | Material definitive agreement | −15.0% (−15.4% vs SPY) | −2.2% (−0.2% vs SPY) | — |
| Aug 7, 2026 | Insider sale | Cann Cynthia Cammett sold $147K | +2.2% (+1.6% vs SPY) | +11.1% (+9.9% vs SPY) | +4.4% (+4.2% vs SPY) |
| Aug 5, 2026 | Form 144 | Form 144: John W Hill plans to sell $106K | +1.3% (+1.5% vs SPY) | +4.3% (+4.4% vs SPY) | +4.7% (+5.5% vs SPY) |
| Aug 5, 2026 | Insider sale | Hill John W sold $106K | +1.3% (+1.5% vs SPY) | +4.3% (+4.4% vs SPY) | +4.7% (+5.5% vs SPY) |
| Aug 4, 2026 | Insider buy | Florance Andrew C bought $2.5M | −0.7% (−2.5% vs SPY) | +4.7% (+2.7% vs SPY) | +6.3% (+5.7% vs SPY) |
| Jul 13, 2026 | 8-K | Directors and officers: departures, appointments, pay | −3.9% (−4.2% vs SPY) | +3.1% (+4.0% vs SPY) | +7.9% (+5.0% vs SPY) |
| Jun 25, 2026 | 8-K | Directors and officers: departures, appointments, pay | −4.0% (−4.1% vs SPY) | −1.5% (−3.2% vs SPY) | −7.5% (−8.2% vs SPY) |
| May 29, 2026 | 8-K | Material definitive agreement | −0.3% (−0.6% vs SPY) | +4.1% (+3.8% vs SPY) | −9.7% (−8.1% vs SPY) |
| Mar 16, 2026 | 8-K | Directors and officers: departures, appointments, pay | 0.0% (−1.0% vs SPY) | −1.7% (+0.2% vs SPY) | −14.9% (−19.9% vs SPY) |
| Feb 13, 2026 | 8-K | Directors and officers: departures, appointments, pay | +1.7% (+1.5% vs SPY) | +6.2% (+6.1% vs SPY) | −1.7% (0.0% vs SPY) |
| Jan 7, 2026 | 8-K | Directors and officers: departures, appointments, pay | −8.6% (−8.3% vs SPY) | −8.3% (−8.6% vs SPY) | −27.6% (−25.5% vs SPY) |
Insiders’ record here
In the year on the chart, Costar Group's insiders reported 1 open-market buy ($2.5M) and 2 sales ($253K). Of the 2 old enough to score, 1 were followed by the stock doing what the trade implied over the next 63 sessions (beating SPY after a buy, lagging it after a sale); the median excess return after a buy was +9.2% and after a sale +5.7%.
Across the whole universe (19,782 scored trades), insider buys beat the market 46% of the time and sales were followed by a lagging stock 61% of the time; buys of $1M or more 39%. Every pattern →
What this kind of 8-K usually did
| Item | 8-Ks | Next session, median | Up next session | 21 sessions, median | Typical size |
|---|---|---|---|---|---|
| 5.02 Directors and officers: departures, appointments, pay | 39,174 | −0.1% | 48% | +0.7% | ±1.4% |
| 1.01 Material definitive agreement | 23,525 | 0.0% | 51% | +1.0% | ±1.4% |
Across every company in the move-odds universe, measured from the close before the filing. Every 8-K item ranked →
Costar Group: every quarter → Live insider trades →
Prices are daily closes; filings and trades are as filed with the SEC (Form 4 within two business days of the trade, 8-K within four of the event). Moves after a mark are the stock's close-to-close change and the same for SPY; they describe the record, not what the next one will do. Not investment advice.