X0201 42003-09-23 0001057352 COSTAR GROUP INC CSGP 0001218615 CARCHEDI FRANCIS C/O COSTAR GROUP, INC. 2 BETHESDA METRO CENTER, 10TH FLOOR BETHESDA MD 20814-5388 0100Chief Financial OfficerCommon Stock, par value $0.01 per share10418DOptions to acquire Common Stock28.152003-09-234A015000A2004-09-232013-09-22Common Stock15000110000DVests over 4 years (3750 on 9/23/2004, 3750 on 9/23/2005, 3750 on 9/23/2006, and 3750 on 9/23/2007)Not applicableFrank A. Carchedi2003-09-24