0000927016-03-002124 S-8 3 20030428 20030428 PEGASYSTEMS INC 0001013857 7374 042787865 MA 1231 S-8 33 333-104788 03667086 101 MAIN ST CAMBRIDGE MA 02142-1590 6173749600 101 MAIN ST CAMBRIDGE MA 02142-1590 S-8 1 ds8.htm FORM S-8 EX-5.1 3 dex51.htm OPINION OF CHOATE, HALL & STEWART EX-23.1 4 dex231.htm CONSENT OF DELOITTE & TOUCHE LLP