0001057352-07-000058 10-Q 5 20070630 20070808 20070808 COSTAR GROUP INC 0001057352 7389 522091509 1231 10-Q 34 000-24531 071036333 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 3012158300 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 10-Q 1 second_quarter200710-q.htm QUARTERLY REPORT EX-31.1 2 exhibit31_1.htm CEO CERTIFICATION EX-31.2 3 exhibit31_2.htm CFO CERTIFICATION EX-32.1 4 exhibit32_1.htm CEO CERTIFICATION 906 EX-32.2 5 exhibit32_2.htm CFO CERTIFICATION 906