National Holdings Corporation, through its subsidiaries, provides financial services. Through the Company's broker-dealer and investment advisory subsidiaries, it offers full service retail brokerage to individual, corporate and institutional clients; provides investment banking, merger and acquisition, and advisory services to micro, small and mid-cap high growth companies; engages in trading securities, including making markets in micro and small-cap National Association of Securities Dealers Automated Quotation (NASDAQ) and other exchange listed stocks, and provides liquidity in the United States Treasury marketplace. Its segments include brokerage and advisory services, and tax and accounting services. The brokerage and advisory services segment includes broker-dealer and investment advisory services, sale of insurance products and licensed mortgage brokerage services. The tax and accounting services segment includes tax preparation and small business accounting services.