The largest nongovernmental regulator of securities firms in the United States is ________.

A) the CFA Institute
B) the Public Company Accounting Oversight Board
C) the Financial Industry Regulatory Authority
D) the Board of Directors of NYSE Euronext

The Financial Industry Regulatory Authority (FINRA) is the largest nongovernmental regulator of securities firms in the United States. The CFA Institute is a global association of investment professionals, not a regulator of securities firms. The Public Company Accounting Oversight Board oversees and regulates accounting firms that audit public companies. The Board of Directors of NYSE Euronext is responsible for overseeing the operations of the New York Stock Exchange and the European Stock Exchange, but it is not a regulator of securities firms.