Specializing in buying proven established horses, Kumin has (and has had) a stake in a number of active and retired racehorses including
Justify,
Exaggerator,
Lady Eli and Wavell Avenue and has been given credit for having "revolutionized the partnership concept." In addition to purchasing stakes in proven racehorses, Kumin has also repeatedly invested in
yearlings such as
Monomoy Girl and
Lady Eli. Kumin is involved in a number of stables and ownership groups including Head of Plains Partners LLC, Madaket Stables, Monomoy Stables, and Sheep Pond Partners. Kumin and his partners usually own around 100 horses at any given time; around 70–75% are fillies. In a 2024 interview with Maxim magazine, Kumin commented that horse racing "has been a really, really good thing for my dad. He’s 82, and it’s given him a new lease on life." Kumin didn't get into horse-racing until much later through close friend Jay Hanley; the pair now comprising ownership group Sheep Pond Partners along with two other friends. After buying his first horse in 2014, Kumin's first high-profile winner was
Lady Eli; purchased that same year. Named after his wife Elizabeth, Lady Eli won the
Breeders' Cup Juvenile Fillies Turf in 2014 and then went on to claim six straight wins before being struck down with
laminitis after stepping on a nail. In 2015, Kumin's Undrafted, which he co-owns with former American football wide receiver
Wes Welker, won the
Diamond Jubilee Stakes at
Royal Ascot. Of Ascot, Kumin commented "It's an incredible place to win. When you stop and look around, the tradition and just the whole scene is different than anywhere in the world." In 2016, Kumin bought a stake in the double Stakes winner Exaggerator in 2016 along with partners including Big Chief Racing and Ron Ortowski. Later that year Kumin was celebrating winning the
Preakness Stakes; one of the Triple Crown Races. Kumin had been in the sport for less than a year when he was crowned
New Owner of the Year for the United States for 2015 at the Thoroughbred Owner Conference in Florida in January 2016.
2016 to 2018 – Justify and the Triple Crown At the
Arlington Million in Chicago in August 2017, Kumin had two successes with Beach Patrol winning the Arlington Million, and Dacita winning the
Beverly D. Stakes. He went on to say he "had an unbelievable day" and that the Million was "the race we've been waiting for a year." Following his horses' performances through the year, Kumin finished fourth in the 2017
Eclipse Award behind
Juddmonte Farms,
Winchell Thoroughbreds and
Godolphin Racing. In March 2018, Kumin bought stakes in two
Kentucky Derby contenders; Audible and
Justify. After My Boy Jack won the
Lexington Stakes and gained 20 qualification points, this would mean that Kumin had three runners in the 2018 Derby. Justify would go on to win the race, with Audible finishing third and My Boy Jack fifth. This topped off a successful two days for Kumin after another of his horses;
Monomoy Girl won the
Kentucky Oaks the same weekend. With two wins, Kumin became the first owner to achieve the Derby-Oaks double in 66 years. Topping off the weekend was another of his horses Yoshida who was victorious in the
Old Forester Turf Classic. Of the weekend, Kumin commented "It was a ridiculous weekend. We had two awesome days with the Derby/Oaks weekend and winning three grade ones." Later that month, Justify landed another victory at the
Preakness Stakes meaning it had won two of the three Triple Crown races with the third to be decided the following month at the
Belmont Stakes. The win meant that Kumin's horses had won the Preakness Stakes in two out of three years. Justify then went on to win the Belmont Stakes, and thus became the 13th Triple Crown winner. In August 2018, Kumin's horse Catholic Boy won the
Travers Stakes in Saratoga Springs, New York. Of the win, Kumin said "The Travers was a bucket list race for me." In November 2018, Monomoy Girl would follow her Kentucky Oaks' win with victory in the
Breeders' Cup Distaff. The following month, Uni took Kumin's Grade 1 wins in 2018 to 24 when it won the
Matriarch Stakes at
Del Mar Fairgrounds. Kumin would finish 2018 with 74 graded wins in total. Of Kumin's 2018, Bob Ehalt wrote that the year was "remarkable" and had "unprecedented accomplishments". The next month saw another of Kumin's highest profile horses leave his roster when Mind Your Biscuits retired, with
Shadai Farm in Japan taking full ownership.
2019 to 2021 – Further wins and Eclipse Award success Kumin's 2019 started well when Coal Front won the $1.5million
Godolphin Mile in Dubai. This was the third straight year that he had won a million-dollar graded stakes on the
Dubai World Cup card. After owning winners of the two out of the four previous Preakness Stakes in Exaggerator and Justify, Kumin would claim a fourth place in 2019 when Warrior's Charge faded in the home stretch. In August, two of Kumin's horse would claim Grade 1 wins with Midnight Bisou claiming victory in the
Personal Ensign Stakes and Mind Control taking first place in the
H. Allen Jerkens Memorial Stakes. In early November, Kumin would take a number of horses to the
Breeders Cup at
Santa Anita Park, California. There were two wins over the weekend for
British Idiom in the
Breeders' Cup Juvenile Fillies, and for Uni in the
Breeders' Cup Mile. There were also places for Midnight Bisou, Shekky Shebaz, and Whitmore. Kumin started 2020 with three of his horses winning their respective categories at the 2019
Eclipse Awards. These included Uni being named
Female Turf Horse of the Year, British Idiom claiming the
Two-Year-Old Filly award and Midnight Bisou victorious in the
Older Dirt Female category. Kumin also saw victories for his two of his horses in February and March when Mr Monomoy won the $400,000
Risen Star Stakes (G2) at
Fair Grounds Race Course, and Whitmore won the $147,000
Hot Springs Stakes for the fourth consecutive year. Later in March, Kumin's Wells Bayou scored a front-running win in the $1 million
Louisiana Derby (G2) at Fair Grounds Race Course. Further wins would follow in April and May for Whitmore in the
Count Fleet Sprint Handicap, and Charlatan in the
Arkansas Derby. Kumin had two more notable wins in June and July when She's a Julie was victorious in the G1
Ogden Phipps Stakes, and Monomoy Girl won the G2
Ruffian Stakes. 2020 also saw wins for another Kumin owned horse when Authentic won the Kentucky Derby and Breeders Cup. These wins along with a second place at the Preakness Stakes and a number of other wins resulted in Kumin's Madaket Stables finishing the year as leading owners (for North American earnings) in an ownership group with
Spendthrift Farm, MyRaceHorse Stable and Starlight Racing. At the 2020 Eclipse Awards (announced in 2021), three of Kumin's horses were successful; Whitmore (
Male Sprinter), Authentic (
Horse of the Year /
3 Year Old Male), and Monomoy Girl (
Older Dirt Female). The Authentic ownership group (of which Kumin's Madaket Stables is part) came second in the
Best Owner category to Godolphin LLC.
Individual horses Kumin has owned a number of high-profile horses with major wins including: •
Authentic - winner of 2020 Kentucky Derby and Breeders' Cup Classic. •
Exaggerator – winner of the 2016 Preakness Stakes before retiring later in the year. Now a breeding stallion at
Winstar Farm. •
Justify – the thirteenth American Triple Crown winner and American Horse of the Year in 2018. •
Lady Eli – American Champion Female Turf Horse of 2017 who won six out of six starts before stepping on a nail and contracting laminitis. •
Monomoy Girl – winner of the Breeders' Cup Distaff and Kentucky Oaks; the filly equivalent of the Kentucky derby. • Mind Your Biscuits – twice-winner of the Dubai Golden Shaheen and the highest earning New-York Bred of all time. • Two Phil's - second-place finisher of the 2023 Kentucky Derby •
National Treasure - winner of 2023 Preakness Stakes and 2024 Pegasus World Cup Invitational •
Midnight Bisou - Champion Older Female Horse in 2019. •
Citizen Bull - winner of 2024 Breeders Cup Juvenile • Spirit of St Louis – winner of 2024 Pegasus World Cup Turf Some of Kumin's other top horses (past and present) include: • A Raving Beauty • Beach Patrol • Charlatan • Dacita • Jimmy P • Mr Monomoy • Rymska • Wavell Avenue • Well's Bayou • Whitmore • World of Trouble • Ya Primo • Yoshida == Lacrosse ==