Invests an Additional $15.6 Million in UBM ParentCo, LLC to Support Strategic Acquisition

HOUSTON, April 21, 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, UBM ParentCo, LLC, doing business as United Business Mail ("UBM" or the "Company"), a leading provider of "marketing mail" commingle services, specializing in optimizing postage, transportation and delivery performance for large-scale mailers. Main Street, along with its co-investor MSC Income Fund, Inc. (NYSE: MSIF) ("MSIF"), made the follow-on investment in UBM to support the Company's strategic acquisition of a leading national provider of asset-light palletized mail consolidation, mail optimization services, freight brokerage, and warehousing and distribution for business to business, or B2B, and business to consumer, or B2C, customers. Main Street's portion of the investment consisted of an additional $15.6 million first lien, senior secured term debt investment. Main Street and MSIF initially invested in UBM in December 2025.

Founded in 1987, and headquartered in Chicago, Illinois, UBM helps clients improve speed-to-market, visibility and cost efficiency across their marketing mail programs through a nationwide logistics network and commingling services. UBM expanded its transportation and logistics capabilities by acquiring Mystic Logistics, a mail consolidation services and freight brokerage company, in December 2025. The acquisition further expands these capabilities and strengthens its ability to support scalable, reliable mail movement nationwide.

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.com  
Zach Vaughan | zvaughan@dennardlascar.com  
713-529-6600

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SOURCE Main Street Capital Corporation