CoStar’s app downloads are accelerating, up 39% YoY so far in 1Q26. Adding new users is always a good sign, but in the case of CoStar, it can be hard to know if it is due to interest in its products or just a big Super Bowl advertising campaign for apartments.com.
In this case, DAUs are also up and Apptopia’s MPI is pointing to better-than-expected growth on the Residential side. The combined mobile data suggests that the positive trends we are seeing on app downloads is real.
Downloads are Accelerating for Both Apartments.com and Homes.com
So far in 1Q26, both of CoStar’s biggest apps – apartments.com and homes.com – are seeing faster YoY growth than in 4Q25. For apartments.com, 1Q26 is on track to be the best growth in years. Meanwhile, homes.com is on track for its fourth quarter in a row of YoY growth.
CoStar’s DAUs are Also on the Rise
Not only are the company’s downloads growing, but DAUs across the whole company are accelerating.
This coordinated download strength and DAU momentum suggests customer acquisition is translating into near-term engagement strength. For investors, accelerating downloads correlates with future revenue upside as long as DAUs also experience an expansion.
CoStar’s MPI is Accelerating Ahead of Consensus
One of the core metrics investors watch for CoStar (CSGP) is Revenue – Residential, as it represents almost half of CoStar’s group revenue.
Among Apptopia’s hundreds of mobile signals, Apptopia’s Mobile Performance Index (MPI) for CoStar shows a multi-year history that tracks movements in CoStar’s Residential Revenue and, by extension, could be associated with how the stock responds when this KPI outperforms or misses expectations.
CoStar’s MPI is accelerating ahead of consensus expectations, showing ~250bps of accelerating sequential growth, while consensus expects a deceleration:
Investors should follow Apptopia’s MPI for CSGP as a key signal of CoStar’s mobile performance heading into Q1 2026.
Mobile Growth Across the Board
CoStar’s mobile metrics show a solid profile ten weeks into Q1 2026. Strong downloads and broad DAU/MAU expansion are encouraging, and an accelerating MPI portends well for Residential Revenue.
Investors should use Apptopia’s data to track whether acquisition-fueled reach, engagement intensity, and growth relative to consensus can foreshadow strong results heading into the next earnings window.
