CoStar Group, Inc.

CoStar Group, Inc. is an American provider of real estate information, analytics, and online marketplaces that generated $3.25 billion in revenue in fiscal 2025 across a commercial real estate data franchise and a rapidly expanding residential property portal network. The company operates the dominant data platform for U.S. commercial real estate professionals, the leading U.S. apartment listing marketplace, and the second-largest for-sale home portal, alongside growing positions in the United Kingdom, Australia, France, and Spain.

This is a story about a deeply entrenched information-services franchise funding an ambitious and expensive entry into residential real estate portals — a market roughly twenty times the size of its legacy commercial end-market — while simultaneously absorbing two multi-billion-dollar acquisitions and a generational technology shift in artificial intelligence. The file turns on a single question: whether the commercial core can sustain the residential investment long enough for Homes.com and the international platform to reach profitable scale, and at what cost to per-share value along the way.

The stock has declined roughly two-thirds from its August 2025 peak of $97 to the low $30s, repricing a company that was once valued at over $30 billion as if the residential bet had already succeeded to one where the market is pricing meaningful skepticism about both the magnitude and the timeline of that payoff. A debt-free balance sheet, a recently authorized $1.5 billion buyback, and management's stated pivot to margin expansion in 2026 make this an unusually well-capitalized battleground.