Portman Ridge Finance Corporation is a business development company specializing in investments in unitranche loans (including last out), first lien loans, second lien loans, subordinated debt, equity co-investment, mezzanine, buyout in middle market companies.

It also makes acquisitions in businesses complementary to the firm's business. It primarily invests in healthcare, cargo transport, manufacturing, industrial & environmental services, logistics & distribution, media & telecommunications, real estate, education, automotive, agriculture, aerospace/defense, packaging, electronics, finance, non-durable consumer, consumer products, business services, utilities, insurance, and food and beverage sectors.

The fund typically invests $1 million to $20 million in its portfolio companies. It provides senior secured term loans from $2 million to $20 million maturing in five to seven years; second lien term loans from $5 million to $15 million maturing in six to eight years; senior unsecured loans $5 million to $23 million maturing in six to eight years; mezzanine loans from $5 million to $15 million maturing in seven to ten years; and equity investments from $1 to $5 million.

The fund targets the companies with EBITDA between $5 million and $25 million. While investing in debt securities, it invests in those middle market firms with EBITDA between $10 million and $50 million and/or total debt between $25 million and $150 million.

It invests in minority, and majority or control equity positions alongside its private equity sponsor partners.