Main Street Announces Follow-On Investment

Invests an Additional $26.0 Million in Trantech Radiator Topco, LLC to Support Strategic Acquisition

HOUSTON, April 1, 2026 /PRNewswire/ -- Main Street Capital Corporation (NYSE: MAIN) ("Main Street") is pleased to announce that it recently completed a follow-on investment in its existing portfolio company, Trantech Radiator Topco, LLC ("Trantech" or the "Company"), an industry leading domestic designer, manufacturer and supplier of branded radiators and cooling systems for transformers used in the generation, transmission and distribution of electric power. Main Street, along with its co-investor MSC Income Fund, Inc. (NYSE: MSIF) ("MSIF"), made the follow-on investment in Trantech to support the Company's strategic acquisition of Transformer Maintenance and Service, Inc. ("TMS"), which is a provider of utility equipment maintenance and repair services for original equipment manufacturers (OEM) and utility customers. Main Street and MSIF provided a portion of the financing necessary to facilitate the acquisition, with the owners of TMS receiving a portion of the acquisition purchase price in equity ownership in Trantech. Main Street's portion of the investment consisted of an additional $24.7 million first lien, senior secured term debt investment and a $1.4 million direct equity investment. Main Street and MSIF initially invested in Trantech in May 2019.

Founded in 1932, and headquartered in Edgefield, South Carolina, Trantech's American made products are sold to transformer OEM and aftermarket customers for repair and replacement applications. Founded in 1978, TMS is a family owned business with long history of providing services that are highly complementary to Trantech's products. The acquisition of TMS enhances Trantech's field service, repairs and refurbishment capabilities and strengthens the Company's ability to support the increasing demands across the electric utility market.

ABOUT MAIN STREET CAPITAL CORPORATION
Main Street (www.mainstcapital.com) is a principal investment firm that primarily provides customized long-term debt and equity capital solutions to lower middle market companies and debt capital to private companies owned by or in the process of being acquired by a private equity fund. Main Street's portfolio investments are typically made to support management buyouts, recapitalizations, growth financings, refinancings and acquisitions of companies that operate in diverse industry sectors. Main Street seeks to partner with entrepreneurs, business owners and management teams and generally provides customized "one-stop" debt and equity financing solutions within its lower middle market investment strategy. Main Street seeks to partner with private equity fund sponsors and primarily invests in secured debt investments in its private loan investment strategy. Main Street's lower middle market portfolio companies generally have annual revenues between $10 million and $150 million. Main Street's private loan portfolio companies generally have annual revenues between $25 million and $500 million.

Main Street, through its wholly-owned portfolio company MSC Adviser I, LLC ("MSC Adviser"), also maintains an asset management business through which it manages investments for external parties, including MSIF. MSC Adviser is registered as an investment adviser under the Investment Advisers Act of 1940, as amended.

ABOUT MSC INCOME FUND, INC.
MSIF (www.mscincomefund.com) is a principal investment firm that primarily provides debt capital to private companies owned by or in the process of being acquired by a private equity fund. MSIF's portfolio investments are typically made to support leveraged buyouts, recapitalizations, growth financings, refinancings and acquisitions of companies that operate in diverse industry sectors. MSIF seeks to partner with private equity fund sponsors and primarily invests in secured debt investments within its private loan investment strategy. MSIF also maintains a portfolio of customized long-term debt and equity investments in lower middle market companies, and through those investments, MSIF has partnered with entrepreneurs, business owners and management teams in co-investments with Main Street utilizing the customized "one-stop" debt and equity financing solutions provided in Main Street's lower middle market investment strategy. MSIF's private loan portfolio companies generally have annual revenues between $25 million and $500 million. MSIF's lower middle market portfolio companies generally have annual revenues between $10 million and $150 million.

Contacts:
Main Street Capital Corporation
Dwayne L. Hyzak, CEO, dhyzak@mainstcapital.com
Ryan R. Nelson, CFO, rnelson@mainstcapital.com
713-350-6000

Dennard Lascar Investor Relations
Ken Dennard | ken@dennardlascar.co
Zach Vaughan | zvaughan@dennardlascar.com
713-529-6600

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