Often called Islamic bonds, or sukuk, the securities comply with Islamic religious principles while providing investors with returns that closely resemble those of conventional bonds. To comply with those religious principles, Islamic bonds are structured differently from conventional bonds. Islamic bonds also avoid financing companies that profit from activities generally prohibited under Islamic law. Even as Islamic bonds became increasingly popular, conventional bonds continued to play an important role in the market. The trend shows how Islamic bonds evolved from a niche financing option into a leading source of corporate funding.