==For Commercial Use==
# Copying copyrighted material for commercial use is absolutely forbidden. Mishnat Yehoshua p. 152 writes that everyone agrees that violating a copyright for commercial use is forbidden because of (1) dina dmalchuta (2) minhag and (3) hasagat gevul. This is obvious from Shevet Halevi 4:202 and many others. Practical Laws of Money p. 117 cites a letter from Rav Karelitz, Rav Elyashiv, and Rav Wosner about how it was forbidden to buy from the person who hacked the bar ilan CD and sold pirated copies because it was helping a sinner.</ref>
==For Personal Use==
# Many poskim hold that it is stealing to copy someone else’s intellectual property or copyrighted material.<ref>Mishnat Yehoshua cites Igrot Moshe 4:40:19, Rav Elyashiv (Mishnat Zchiyot Hayotzer ch. 18, Emek Hamishpat), Teshuvot Vhanhagot 1:829, Netsiv in Meishiv Dvar 24, Minchat Yitzchak 9:153, and Shevet Halevi 10:276 forbid copying copyrighted materials because it is stealing intellectual property. Even though the law isn't enforced and many people copy the copyrighted materials that doesn't permit it since according to these poskim copying intellectual property is stealing which is forbidden even if many others do it. Mishnat Yehoshua p. 154 quotes Rav Asher Weiss as holding that it is stealing to violate a copyright. This is also implied from Rav Shimon Schkop b"k siman 1. This is also the conclusion of Piksei Din of Yerushalayim Mamonot Ubirurei Yuchsin v. 13 p. 293.