Corundum Group

Chairman Tom Stoner, who co-founded the firm in 1996 after working at Boeing's venture arm, leads the broad investment strategy. David Stoner, as President, oversees day-to-day operations and has been increasingly involved in sourcing and structuring the firm's private equity platform. The firm builds a specific investment committee around each transaction, drawing on a network of Rocky Mountain operating partners, though final discretion rests with the Stoner family and a small group of senior advisors.

Corundum historically avoids broad auction processes, relying instead on a network of regional operating partners, former portfolio company executives, and long-tenured intermediaries in the Western US. The firm targets sectors where local market knowledge matters — industrial technology, healthcare services, and business services — and leverages multi-decade relationships with family-owned businesses seeking a patient capital partner. This approach results in a deliberate cadence of 2-3 platform investments per year.

Corundum is structured as a multi-family office, serving a small, confidential group of wealthy families concentrated in the Western United States. The Stoner family itself anchors the partnership, but the firm has deliberately broadened its capital base beyond a single fortune, creating a shared platform for direct investments that would be difficult for most families to access individually.

The firm overwhelmingly prefers direct investments. In private equity, Corundum pursues control buyouts in the lower middle market, and in real estate it acquires and operates income-producing multifamily and industrial assets directly. On occasion, the firm has participated as a limited partner in specialized funds where a co-investment right or sector-specific expertise offered a clear path to a later direct deal, but fund commitments are auxiliary to the core direct strategy.

Corundum targets companies with EBITDA typically in the $2–10 million range, a segment where institutional private equity participation is structurally lighter. Deal sizes span roughly $10–50 million in enterprise value, and the firm can write equity checks of $5–20 million from its pooled family capital, sometimes syndicating co-investment across its client families for larger transactions.

The firm does not publicly disclose the specific origins of its client families' wealth, consistent with standard practice among multi-family offices serving private Western US fortunes. Public record indicates the Stoner family's early capital derived from corporate venture and industrial experience, but the wider client base is understood to include liquidity from industrials, technology, and real estate enterprises.

Corundum will co-invest alongside external GPs on a highly selective basis, primarily when the GP brings a specific operational resource or sector network that complements the firm's own. The firm insists on direct board representation and governance parity in all co-investments, and it refuses blind-pool co-invest without an independent, deal-level due-diligence process.