Our Story
Get to Know Us
Midstone Service Group is an operator-led platform focused on acquiring and building essential service businesses for the long term. With both our founders being from Michigan, Midstone reflects a Midwest mindset—practical, hardworking, and built on respect for the people who do the work.
The name Midstone comes from two ideas: “Mid,” representing our Midwest roots, and “Stone,” reflecting our commitment to owning and building businesses that are durable, enduring, and designed to last. We partner with founders and management teams to strengthen operations, invest in people and systems, and create businesses that compound value over time.
The Team
Temi Hambraeus
Co-Founder & Managing Partner
Temisan Hambraeus is a co-founder of Alstra Group and leads capital allocation, transaction execution, and financial infrastructure. His background includes private equity investing at KKR and Apollo, company creation at Juxtapose, and operating roles building scalable growth platforms. Temisan partners with leadership teams to structure disciplined growth and align incentives for long-term value creation.
517-974-8323
Zonta Owens
Co-founder & Managing Partner
Zonta Owens is a co-founder of MSG and focuses on operating performance, organic growth, and building strong teams across the platform. He brings a background in engineering, management consulting at Bain & Company, and hands-on experience acquiring and operating service businesses through Pondr Group. Zonta works closely with management teams and field operators to improve systems, accountability, and long-term business durability.
313-459-1665
Denise Aronson
Advisor
Denise Aronson is the founder of Safety Partners, Inc., a life science environmental health and safety (EHS) consulting firm she started in 1992. Over more than three decades, she built Safety Partners into a trusted provider of customized EHS programs for hundreds of science and technology companies across the U.S.
Raghdan AlKoury
Advisor
Raghdan Alkhoury is a Partner at Bain & Company, where he advises organizations on strategy, operations, and performance improvement across induatrials and Manufacturing. Prior to Bain, Raghdan worked in technical and engineering roles at Shell and Petrofac, giving him a strong foundation in complex operational environments. He holds an MBA from INSEAD and brings a blend of strategic insight and practical problem-solving to his work.
