Sullivan Street Partners

It is a London-based private equity firm that acquires controlling stakes in UK lower mid-market companies, typically with enterprise values between £10 million and £100 million. The firm specializes in situations requiring substantial operational improvement — corporate carve-outs, succession-driven sales, and distressed or underperforming assets. Its principals are directly involved in post-acquisition transformation, reflecting a hands-on, restructuring-informed investment style.

Managing Partners Layton Tamberlin and Richard Sanders lead all investment decisions. Both spent formative years in structured finance and restructuring roles at GE Capital and Close Brothers before founding the firm in 2011. The partnership is deliberately compact, with deal execution led by the senior principals rather than a large multi-tiered investment committee.

The firm is generalist within the UK lower mid-market but its most publicly documented investments cluster around healthcare services (notably veterinary platforms), industrial services, and environmental infrastructure. Previously held assets include Bioganix, an organic waste processing business, and Two Counties Vets, a veterinary group. The firm avoids sectors dominated by rapid technological obsolescence, favoring businesses with tangible operational levers.

The firm relies heavily on proprietary sourcing through its principals' long-standing UK corporate networks and restructuring advisory relationships. Because it pursues off-market, complex situations — distressed carve-outs, family succession disposals, and underperforming corporate divisions — it often sees transactions that never reach broad auction processes. Large banks and accountancy practices in the UK mid-market restructuring community are a key origination channel.

Standard buyout funds in the UK mid-market generally acquire stable, cash-generative businesses and apply leverage and multiple-arbitrage to generate returns. Sullivan Street specifically targets businesses requiring deep operational rehabilitation — under-managed, distressed, or orphaned assets where standard sponsors see too much execution risk. The firm's principals directly run transformation programs post-close, functioning more like turnaround operators than conventional financial sponsors.