SIFMA | 28,500 followers on LinkedIn. SIFMA is the voice of the nation's securities industry. We advocate for effective and efficient capital markets. | SIFMA is the voice of the nation’s securities industry, bringing together the shared interests of hundreds of broker-dealers, investment banks and asset managers. We advocate for effective and resilient capital markets. SIFMA is the leading trade association for broker-dealers, investment banks and asset managers operating in the U.S. and global capital markets.