About Us

A World Class Thoroughbred Investment Syndicate

Stone Bridge Investments is a thoroughbred investment syndicate founded in 2018

The syndicate currently is currently made up of 59 members from across the United States. The founder, Jeff Prunzik, owns Stone Bridge Farm and is based in Pittsburgh, Pennsylvania. Stone Bridge Investments currently owns 12 horses:

The syndicate specializes in pinhooking its assets, predominately purchasing horses as weanlings and selling them as yearlings. Stone Bridge Investments has sold assets at the premier thoroughbred auctions in the world, including Fasig-Tipton’s Saratoga Sale and Keeneland’s November Breeding Stock Sale.


Jeff Prunzik

Managing Member

Born and raised in Pittsburgh, Jeff graduated from Westminster College in New Wilmington PA with a degree in Business. With a background in commercial real estate, Jeff has built a portfolio of holdings in Western PA consisting of industrial, retail and office properties. Along with his brother Dan, Jeff co-founded and later sold (2012) a paper recycling & shredding operation called The Paper Exchange. He also co-founded and currently owns Olive or Twist, a popular bar/restaurant in Downtown Pittsburgh. Jeff and his wife Melissa purchased Stone Bridge Farm in 2017. They are the founding partners in Stone Bridge Investments since inception in 2018.

Mike Heitzmann

General Manager/Founding Partner

A native of New Orleans, Mike began his career hot walking on weekends and summers for his father Roger, who trained horses of 30+ years. His three brothers are all in the Thoroughbred industry. Roger is the Secretary-Treasurer for the Louisiana Thoroughbred Breeders Association; David is the Racing Secretary at Louisiana Downs, and Eric is a multiple stakes winning trainer.

After leaving college off a football scholarship, Mike went back to his roots on the track, and started his work as a racing official at the Fair Grounds, ThistleDown, and other notable tracks. He then spent 5 years as a jockey agent for riders Ronald Franklin, Tracy Hebert, Mario Torres, etc.

Mike settled down in Lexington and took a position as a stallion groom at Vinery. He soon was named stallion manager, a position he enjoyed for more than 12 years. During their years of operation, he managed Red Ransom, Pioneerof the Nile, More Than Ready, Congrats, Runaway Groom, and many other successful stallions. While at Vinery, Mike began building a band of broodmares. His successes include a homebred More Than Ready yearling that sold for $320,000 from his own consignment. He is a founding partner of Stone Bridge Investments. With 30+ years in the industry, Mike’s vast experience speaks for itself.

Michael Donnelly

President and Chief Financial Officer

Mike has been a manager of financial assets for more than 30 years. During this time, he had senior leadership positions at CS McKee, LAPP Capital, American Century and Federated Hermes. A specialist in equity portfolio management, Mike holds a Master of Management in International Business and International Finance from the Kellogg School of Management at Northwestern University and an undergraduate degree from Yale University. He is a Chartered Financial Analyst. A Pittsburgh native and a lifelong horse enthusiast, Mike is proud to be a member of Stone Bridge Investments since 2018.

Lexington, KY

Stone Bridge Farm

The home of our equine assets

It is a 195 acre full-service facility located in the heart of Central Kentucky’s legendary Bluegrass region. Five champions, including Eclipse Award and Breeders’ Cup winners Meadow Star and Action This Day, and dozens of stakes winners have been a part of Stone Bridge legacy for more than thirty years. That commitment to excellence continues as the Prunzik family embarks upon their stewardship of this enduring tradition.