The Jockey Club, formed on February 9, 1894, is the keeper of the North American Stud Book. It came into existence after James R. Keene spearheaded a drive in support of racehorse trainers who had complained about the Board of Control that governed racing in New York State.

History

On its formation, the Jockey Club included the existing members of the Board of Control and was overseen by seven appointed stewards. Its twenty-seven founding members included prominent and wealthy sportsmen such as Philip J. Dwyer, John A. Morris, William Kissam Vanderbilt, and William Collins Whitney.
Founding officers:

• Chairman - John Hunter (co-owner of Saratoga Race Course)

• Vice Chairman - James R. Keene (stockbroker, racehorse owner/breeder)

• Secretary-Treasurer - Frank K. Sturgis (President of the New York Stock Exchange)

Founding Stewards:

• John Hunter

• James R. Keene

• Frank K. Sturgis

• August Belmont, Jr.

• J. O. Donner

• Col. W. H. Thompson

• Gideon Lee Knapp

The Jockey Club is the authority for all thoroughbred horses in North America, Canada, and Puerto Rico and maintains offices in New York City and Lexington, Kentucky. The Registry maintained by the Club, called the American Stud Book, dates back to the club's founding and contains the descendants of those horses listed, as well as horses imported into North America up to the present. The Registry is consulted by multiple breeders in determining matings to advance or avoid.

Participants in the Registry program agree to allow the Club to conduct genetic testing to verify parentage as well as arbitrating any disputes between owners. The Jockey Club has taken the position that it will not allow for cloned thoroughbreds to be registered in the Stud Book, making it impossible for such horses to compete in most races. The Club has consistently prohibited artificial insemination throughout its history, only allowing the registration of horses through "natural" procreation.

Naming of foals is also controlled by the Club and includes a number of conventions. Names may not consist of more than 18 letters (with spaces and punctuation marks counting as letters), contain initials such as C.O.D., F.O.B., etc., or end in "filly," "colt," "stud," "mare," "stallion," or any similar horse-related term. Names may also not end with a numerical designation such as "2nd" or "3rd," whether or not such a designation is spelled out. Names of persons may not be used unless written permission to use their name is on file (examples of such permission are actor Jack Klugman, whose namesake competed in the Kentucky Derby, and tennis star Chris Evert, whose namesake is in the National Museum of Racing and Hall of Fame). The names of "notorious" people may never be used, nor can namesakes of racetracks, races, or stable names. Trademarks and copyrighted names are similarly not allowed as are vulgar, obscene or offensive ones. The list also protects names of currently active horses as well as horses enrolled in the National Museum of Racing and Hall of Fame or other well-known horses, including winners of the Kentucky Derby, Preakness, Belmont Stakes, Jockey Club Gold Cup or Breeders' Cup events.

Created in 1984, The Jockey Club Research Foundation was merged with the Grayson Foundation, established in 1940 by George D. Widener, Jr., William Woodward, Sr. and John Hay Whitney, amongst others. It is now known as the Grayson-Jockey Club Research Foundation, Inc.

The Jockey Club formed the National Thoroughbred Racing Association (NTRA) in 1998 with the Breeders' Cup Limited, Thoroughbred Owners and Breeders Association, Keeneland Association, Oak Tree Racing Association and the National Thoroughbred Association. The NTRA lobbies on behalf of the horse racing industry and sets the rules for horse racing throughout the United States.

The Jockey Club is not to be confused with similarly-named private firms with that name that operate racetracks. For example, the Maryland Jockey Club, owned by Magna Entertainment Corporation, is the parent of Pimlico Race Course and Laurel Park Racecourse in Maryland. Aqueduct Racetrack in New York City was founded by the Queens County Jockey Club, now part of the New York Racing Association.

Experimental Free Handicap

Since 1935 the Jockey Club has compiled the Experimental Free Handicap, a weight-based assessment of the previous year's 2-year-olds based on a theoretical race at a distance of 1 ¹/16 miles.