Sterling Investment Partners

Sterling executes control-oriented buyouts and growth recapitalizations in North American middle-market services and light manufacturing. The firm targets companies with enterprise values between $100 million and $500 million, writing equity checks of $50 million to $150 million. The strategy is sector-generalist but concentrated within business services, route-based logistics, essential infrastructure, and specialized outsourcing. Sterling acts as a majority or controlling investor and supplements organic growth with add-on acquisitions.

Sterling manages a single buyout strategy through a series of institutional commingled funds. The firm closed its third flagship vehicle, Sterling Investment Partners III, at $543 million in 2018. The partnership has not launched adjacent credit, venture, or real estate vehicles. Limited partners have historically included university endowments, foundations, pension funds, and family offices, though the firm does not publicly disclose its current LP composition.

Charles W. Santoro, Douglas L. Newhouse, and M. William Macey Jr. co-founded Sterling in 2004. The three principals previously worked together at Nassau Capital, the private equity firm that managed investments for Princeton University's endowment, and later at CVC Capital Partners. Macey transitioned to a Senior Advisor role, while Santoro and Newhouse continue as Managing Partners leading the firm's day-to-day operations and investment decisions.

Sterling's investment mandate is exclusively North American, with a focus on the United States and, to a lesser extent, Canada. Within that geography, the firm is agnostic about location, seeking founder-owned or family-held businesses with durable revenue profiles regardless of region. The firm has historically sourced deals across the Midwest, Southeast, and Northeast United States.

Sterling has deliberately avoided the path of scaling into a multi-strategy, multi-product asset manager. The firm has raised three funds of comparable size since 2004, maintained the same leadership structure, and avoided international expansion. This creates a distinctive alignment profile — the partnership does not face pressure to deploy capital across new strategies to justify a higher management-fee base. For allocators, this offers concentrated, strategy-pure exposure to US middle-market services buyouts.

Sterling's transaction structure, writing checks of $50 million to $150 million from a sub-$600 million fund, naturally accommodates co-investment alongside limited partners on larger transactions. While the firm does not publicly market a formal co-investment program, its deal size relative to fund scale suggests that select LPs have historically been offered co-investment capacity on a deal-by-deal basis.

Sterling Investment Partners does not publicly disclose a dedicated corporate philanthropic vehicle or foundation structure tied to the firm. The firm's limited partner base has historically included foundations and endowments, but the partnership itself operates as a for-profit private equity manager without a separately branded impact or philanthropic arm (per public record).