Exhibit 99.1

	NEWS RELEASE
	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

Main Street Announces Third Quarter 2025 Private Loan Portfolio Activity

HOUSTON – October 9, 2025 – Main Street Capital Corporation (NYSE: MAIN) (“Main

Street”) is pleased to announce the following recent activity in its private loan portfolio. During

the third quarter of 2025, Main Street originated new or increased commitments in its private

loan portfolio of $117.3 million and funded total investments across its private loan portfolio

with a cost basis totaling $113.3 million.

The following represent notable new private loan commitments and investments during the third

quarter of 2025:

•$27.6 million in a first lien senior secured term loan, $3.9 million in a first lien senior

secured revolver, $3.9 million in a first lien senior secured delayed draw term loan and

$1.5 million in equity to a provider of HVAC and plumbing installation services to

multifamily and commercial end markets;

•Increased commitment of $14.9 million in an incremental first lien senior secured term

loan and $3.9 million in an incremental first lien senior secured revolver to a provider of

highly technical specialty services to datacenters and various other diverse end markets;

•$6.3 million in a first lien senior secured term loan, $3.1 million in a first lien senior

secured revolver, $6.3 million in a first lien senior secured delayed draw term loan and

$0.6 million in equity to a provider of new and refurbished pad mounted transformers to

datacenter, commercial and industrial end markets;

•$10.1 million in a first lien senior secured term loan, $2.5 million in a first lien senior

secured revolver, $2.8 million in a first lien senior secured delayed draw term loan and

$0.7 million in equity to a provider of custom glass fabrication, installation and specialty

coating solutions;

•Increased commitment of $10.5 million in an incremental first lien senior secured term

loan to a manufacturer of chemicals and lubricant additives serving large specialty

chemical companies; and

•Increased commitment of $4.9 million in an incremental first lien senior secured term

loan and $0.2 million in incremental equity to a provider of positive displacement meters,

ultrasonic meters, turbine meters, tank truck meters, loading systems, terminal

management systems and aftermarket spare parts across the energy value chain.

As of September 30, 2025, Main Street’s private loan portfolio included total investments at cost

of approximately $1.9 billion across 86 unique companies. The private loan portfolio, as a

percentage of cost, included 94.0% invested in first lien senior secured debt investments and

6.0% invested in equity investments or other securities.

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. MSC Adviser is registered as an investment adviser under the Investment

Advisers Act of 1940, as amended.