Stock split history for CoStar Group (CSGP)

Stock splits history (since IPO on July 1, 1998)

Cumulative multiple is the running product of split factors from the chronologically oldest row through each date. Rows are listed newest-first, so the cumulative column reads forward in time from the bottom of the table toward the top.

Pre-split price is the final regular-session close on a trading day strictly before the split calendar date. Post-split price is the first session open on or after that date. Both values come from unadjusted end-of-day bars for the company's primary listing.

The Type column reflects the data feed's event category (for example stock split vs stock dividend). When the feed labels a generic split but the ratio is reverse (e.g. 1:10), we show reverse stock split. Optional editorial context for a row appears next to the split ratio as an info icon (hover or keyboard focus on desktop; tap on mobile). The same text is listed under Row notes when that block is expanded.

Wondering why some rows show ratios like 51:50 or 2000:1973? Read: stock split ratios explained →How the cumulative column is computed: cumulative split multiplier explained. For ratios driven by spin-offs, see spin-offs explained. Or read the methodology for how prices and cumulative multiples are computed.