The term AMEX COMPETITOR can be summarized by two crossword solutions: NASDAQ and CITI. NASDAQ stands for the National Association of Securities Dealers Automated Quotations, which is an American stock exchange that lists more than 3, 000 companies. CITI stands for Citigroup Inc., which is a multinational investment bank and financial services corporation. Both NASDAQ and CITI are competitors to American Express (AMEX).