Delta Sigma Pi | 54,442 followers on LinkedIn. Delta Sigma Pi is the nation's largest and first co-ed, professional business fraternity that encourages personal and professional development of men and women pursuing careers in business. The Fraternity is one of the most diverse Greek organizations supporting scholastic, professional and service events on campuses and in communities. Delta Sigma Pi provides high-quality training and events to shape ethical leaders of tomorrow in business, communities, and the world at large.