PC-SIG was a software retailer founded in 1984 by Richard Peterson that specialized in the distribution of PC shareware. Its name stands for "IBM-PC Special Interest Group". The company distributed Jon Walker's PC-based adventure system, including his adventure The Ice Cave, on its disks 296, 297, 1038, and 1039. The company also gave Walker's system an entry in The PC-SIG Encyclopedia of Shareware.
PC-SIG held a "Create Your Own Adventure Module Contest" in approximately 1987, yielding at least two adventures, Cronum's Castle and Lord of the Underland. These adventures were distributed as disks 720 and 721 in the PC-SIG catalog but by 1990, in the eighth edition of the PC-SIG Library on CD-ROM, Underland was listed as "unsupported" and Cronum was removed from the catalog entirely.
PC-SIG was located at 1030D East Duane Avenue in Sunnyvale, California. It went out of business in 1992 or 1993, with the fourteenth (and final) edition of its library released in 1994.