Syndicate baseball or syndicate ownership refers to a practice in the National League in the 1890s in which one group could own several teams in the league. The practice soon proved detrimental when some of these groups decided to favor one of their franchises at the expense of the other. Most notorious were brothers Frank and Stanley Robison, who owned both the St. Louis Perfectos and the Cleveland Spiders, and moved all of the Spiders' best players to St. Louis before the 1899 season. The Spiders ended up as the worst team in Major League history.
Other syndicate owners include John Brush, who had stakes in both the New York Giants and Cincinnati Reds, and the ownership groups of the Brooklyn Bridegrooms and Baltimore Orioles, who were similarly inter-linked. In all cases, incestuous relations among owners led to movements of players highly detrimental to one of the two partner franchises. It thus became clear that there was an inherent conflict of interest in the practice.
Syndicate ownership was outlawed after the 1899 season, when the National League contracted by four teams. There have been a few instances of owners ending up with stakes in more than one team since, but these have usually involved small minority positions.