"Many forms of conduct permissible in a workaday world for those acting at arm’s length, are forbidden to those bound by fiduciary ties. . . . Not honesty alone, but the punctilio of an honor the most sensitive, is then the standard of behavior.” Thus did Judge Benjamin Cardozo articulate fiduciary duties in his seminal 1928 opinion in Meinhard v. Salmon, a dispute between business partners. This blog surveys the most recent appellate-level New York court decisions on breach of fiduciary duty claims, with a particular emphasis on the fiduciary relationships among businesspeople. These claims arise frequently in commercial litigation, and are flexible enough to encompass a wide range of conduct. Corporations, limited liability companies, partnerships, and businesspeople in general would be well served by keeping up with developments in this important body of law.