0001057352-08-000065 10-Q 6 20080630 20080725 20080724 COSTAR GROUP INC 0001057352 7389 522091509 1231 10-Q 34 000-24531 08969360 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 3012158300 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 10-Q 1 second_quarter2008form10-q.htm 2Q 2008 10-Q EX-10.1 2 addendum4_tolease.htm ADDENDUM NO. 4 TO OFFICE LEASE EX-31.1 3 exhibit31_1.htm SEC CEO CERT EX-31.2 4 exhibit31_2.htm SEC CFO CERT EX-32.1 5 exhibit32_1.htm SEC CEO 906 CERT EX-32.2 6 exhibit32_2.htm SEC CFO 906 CERT