A coalition of religious investors wants officials at 27 major U.S. companies to look deeper into the role human trafficking may play in the operation of their firms. The investors, who are members of the Interfaith Center on Corporate Responsibility and include about 80 Catholic religious congregations and health care providers, are asking companies like Costco, American Airlines and Kohl’s to stop doing business with suppliers who violate basic human rights and to train employees to recognize trafficked people in their midst. The I.C.C.R. correspondence, in the form of an investor statement, offers an explanation of the prevalence of human trafficking in various industries, describes in detail legislative steps taken to control it and outlines actions the coalition wants the companies to take in order to end demand for what is widely considered modern-day slavery. The statement, sent to clothing, food, travel and tourism, agricultural, technology and retail firms, was timed to coincide with the release of the 2011 Trafficking in Persons report by the State Department.