[2] Tabor's grandparents were Russian-Jewish immigrants, originally called Taborosky, who had moved to London from Vilna, then under the control of the Russian Empire, now the capital of Lithuania.

Tabor had been looking for a horse to race in America and had been pointed for advice to John Magnier by a mutual friend, J.P. McManus.

[2][5][6] His great successes as an owner, however, came in association with the expert Irish horsemen connected to the Coolmore Stud of John Magnier.

His investment allowed Magnier to become once again a major buyer in the top yearling sales, a role he had not played since the mid-1980s when he had acted in conjunction with Robert Sangster and other associates.

[8] Tabor became the owner and co-owner of an extraordinary catalogue of some of the world's best racehorses, generally owning the Coolmore horses in a three-way partnership with Magnier and his wife Sue, and later with Derrick Smith, who became involved in the mid-2000s.

Tabor was also the breeder, as well as the owner, of Giant's Causeway, winner of numerous Group One races, and in 1995 his Hurricane Run was voted the world's top-ranked racehorse by the International Federation of Horseracing Authorities.

Discussing the economics of Coolmore's extremely successful breeding operation, Tabor said: "I get enormous pleasure out of the horses but, it goes without saying, that you're trying to make stallions.

"[5] Tabor gained a reputation as a shrewd, daring and successful gambler, whose actions could dramatically affect the odds being offered on a horse.

[3] His later horseracing associate, Derrick Smith, told The Racing Post that when he was working with Ladbrokes in the 1980s they had to stop taking Tabor's bets.

[12][13][14][15] In addition, Tabor, Magnier, McManus, and another Irish associate and Sandy Lane owner, Dermot Desmond, collectively owned 60 per cent of the Next Generation chain of fitness clubs sold to London & Regional Properties for around £200 million in 2006.

[21] Tabor's other business dealings include an investment in two London hotels[22] and a failed attempt in 1996 to buy West Ham United football club, whom he has supported since he was a boy.