The principal owner for one of Australia's most successful
horse trainers,
Bart Cummings, Tan had a successful working relationship with Cummings for more than thirty years until the latter's death in 2015. He owned at least a share in most of Cummings' well-known horses, including
Think Big (co-owned with Queensland property developer Rick O'Sullivan and then joined by
Tunku Abdul Rahman), winner of back-to-back
Melbourne Cups in 1974 and 1975, as well as the multiple Group One winner,
Saintly. He was the owner of the
2008 Melbourne Cup winner
Viewed, and is one of four thoroughbred owners to win the Melbourne Cup four Times. He also owned 2009 and 2010
Cox Plate winner
So You Think, and the winner of the 2009
Crown Oaks, Faint Perfume. Tan owned a
stud farm located along the
Wingecarribee River at
Burradoo, New South Wales that he named Think Big Stud. ==Chess==