Golub Capital BDC : Overview of Proposed Merger With Golub Capital BDC 3, Inc.

GOLUB CAPITAL BDC, INC.

("GBDC")

OVERVIEW OF PROPOSED MERGER WITH

GOLUB CAPITAL BDC 3, INC. ("GBDC 3")

MAY 2024

CONFIDENTIAL | © 2024 GOLUB CAPITAL LLC

Disclaimer

Forward-Looking Statements

This communication may contain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Statements other than statements of historical facts included in this communication may constitute forward-looking statements and are not guarantees of future performance or results and involve a number of risks and uncertainties. Actual results may differ materially from those expressed or implied in the forward-looking statements as a result of a number of factors, including those described from time to time in filings with the Securities and Exchange Commission. GBDC undertakes no duty to update any forward-looking statement made herein. All forward-looking statements speak only as of the date of this communication.

Some of the statements in this communication constitute forward-looking statements because they relate to future events, future performance or financial condition or the two-step merger of GBDC 3 with and into GBDC (collectively, the "Mergers"), along with the related proposals for which stockholder approval will be sought (collectively, the "Proposals"). The forward-looking statements may include statements as to: future operating results of GBDC and GBDC 3 and distribution projections; business prospects of GBDC and GBDC 3 and the prospects of their portfolio companies; and the impact of the investments that GBDC and GBDC 3 expect to make. In addition, words such as "may," "might," "will," "intend," "should," "could," "can," "would,"

"expect," "believe," "estimate," "anticipate," "predict," "potential," "plan" or similar words

indicate forward-looking statements, although not all forward-looking statements include these words. The forward-looking statements contained in this communication involve risks and uncertainties. Certain factors could cause actual results and conditions to differ materially from those projected, including the uncertainties associated with (i) the timing or likelihood of the Mergers closing; (ii) the expected synergies and savings associated with the Mergers; (iii) the ability to realize the anticipated benefits of the Mergers, including the expected elimination of certain expenses and costs due to the Mergers; (iv) the percentage of GBDC and GBDC 3 stockholders voting in favor of the proposals submitted for their approval; (v) the possibility that competing offers or acquisition proposals will be made; (vi) the possibility that any or all of the various conditions to the consummation of the Mergers may not be satisfied or waived; (vii) risks related to diverting management's attention from ongoing business operations; (viii) the risk that stockholder litigation in connection with the Mergers may result in significant costs of defense and liability; (ix) changes in the economy, financial markets and political environment, including the impacts of inflation and rising interest rates; (x) risks associated with possible disruption in the operations of GBDC and GBDC 3 or the economy generally due to terrorism, war or other geopolitical conflict (including the current conflict between Russia and Ukraine), natural disasters or global health pandemics, such as the COVID-19 pandemic; (xi) future changes in laws or regulations (including the interpretation of these laws and regulations by regulatory authorities); (xii) changes in political, economic or industry conditions, the interest rate environment or conditions affecting the financial and capital markets that could result in changes to the value of GBDC's or GBDC 3's assets; (xiii) elevating levels of inflation, and its impact on GBDC and GBDC 3, on their portfolio companies and on the industries in which they invest; (xiv) combined company's plans, expectations, objectives and intentions, as a result of the Mergers; (xv) the future operating results and net investment income projections of GBDC, GBDC 3, or, following the closing of one or both of the Mergers, the combined company; (xvi) the ability of GC Advisors to locate suitable investments for the combined

company and to monitor and administer its investments; (xvii) the ability of GC Advisors or its affiliates to attract and retain highly talented professionals; (xviii) the business prospects of GBDC, GBDC 3 or, following the closing of one or both of the Mergers, the combined company and the prospects of their portfolio companies; (xix) the impact of the investments that GBDC, GBDC 3 or, following the closing of one or both of the Mergers, the combined company expect to make; (xx) the expected financings and investments and additional leverage that GBDC, GBDC 3 or, following the closing of one or both of the Mergers, the combined company may seek to incur in the future; and (xxi) other considerations that may be disclosed from time to time in GBDC's and GBDC 3's publicly disseminated documents and filings. GBDC and GBDC 3 have based the forward-looking statements included in this press release on information available to them on the date of this communication, and they assume no obligation to update any such forward-looking statements. Although GBDC and GBDC 3 undertake no obligation to revise or update any forward-looking statements, whether as a result of new information, future events or otherwise, you are advised to consult any additional disclosures that they may make directly to you or through reports that GBDC and GBDC 3 in the future may file with the SEC, including the Joint Proxy Statement (each as defined below), annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K.

Additional Information and Where to Find It

This communication relates to a proposed business combination involving GBDC and GBDC 3, along with the related Proposals for which stockholder approval will be sought. In connection with the Proposals, each of GBDC and GBDC 3 intend to file relevant materials with the SEC, including a registration statement on Form N-14, which will include a joint proxy statement of GBDC and GBDC 3 and a prospectus of GBDC (the "Joint Proxy Statement"). This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act. STOCKHOLDERS OF EACH OF GBDC AND GBDC 3 ARE URGED TO READ ALL RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING THE JOINT PROXY STATEMENT OF GBDC AND GBDC 3 REGARDING THE PROPOSALS WHEN IT BECOMES AVAILABLE, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS THERETO, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT GBDC, GBDC 3, THE MERGERS AND THE PROPOSALS. Investors and security holders will be able to obtain the documents filed with the SEC free of charge at the SEC's web site, http://www.sec.gov or, for documents filed by GBDC, from GBDC's website at http://www.golubcapitalbdc.com.

Participants in the Solicitation

GBDC and GBDC 3 and their respective directors, executive officers and certain other members of management and employees of GC Advisors and its affiliates, may be deemed to be participants in the solicitation of proxies from the stockholders of GBDC and GBDC 3 in connection with the Proposals. Information regarding the persons who may, under the rules of the SEC, be considered participants in the solicitation of the GBDC and GBDC 3 stockholders in connection with the Proposals will be contained in the Proxy Statement when such document becomes available. This document may be obtained free of charge from the sources indicated above.

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Process for Evaluating Potential Merger with GBDC 3

GBDC's Board of Directors - along with the independent directors' financial advisor and legal counsel - has gone through a careful, methodical process to evaluate a potential merger with GBDC 3 and believes that it is:

Good for existing stockholders

Good for new stockholders

Good for GBDC

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Summary of Transaction Key Terms

	−	Stock-for-stock merger with shares of GBDC 3 common stock to be exchanged for shares of GBDC common stock
Merger Structure	−	The number of shares of GBDC common stock to be received by GBDC 3 stockholders to be determined at merger close based upon (i) the
	Net Asset Value ("NAV") per share of GBDC 3 and GBDC, and (ii) the market price of GBDC common stock
	−	Combined company to continue to trade under the ticker symbol "GBDC" on the Nasdaq
	−	$8.8 billion of total assets1
Pro Forma Balance	−	Investments in 367 portfolio companies with an average position size of less than 0.3%1
−	No change to investment strategy focused on first lien, senior secured loans
Sheet
−	No change to target leverage (0.85x - 1.25x), pro forma GAAP debt-to-equity estimated to be ~1.05x (200% asset coverage minimum at
		GBDC 3)1
	−	No change to GBDC base management fee rate of 1.0%
Fee Structure	−	GBDC income and capital incentive fee rate to be reduced to 15%, to become permanent upon closing of the merger2
	−	No change to income incentive fee hurdle rate of 8%
	−	Affirmative vote of (i) a majority of the stockholders of GBDC 3 and (ii) a majority of a quorum of stockholders of GBDC
Closing Approvals	−	Regulatory and other customary approvals
	−	Amendment of the Investment Advisory Agreement of GBDC (no stockholder vote required)
	−	Concurrent with announcement of the merger, GBDC's Board of Directors (the "Board") declared a quarterly distribution of $0.39 per
		share, which was paid in March 2024, an increase from the quarterly distribution of $0.37 per share declared in November 20233
Dividends	−	Existing variable supplemental distribution framework to remain in effect
	−	In addition, the Board expects to declare a series of post-merger special distributions related to undistributed taxable income in the
		aggregate amount of $0.15 per share, to be paid in three equal quarterly installments of $0.05 per share4
Post-Closing Share	−	Existing $150 million GBDC share repurchase plan will remain in effect
Purchase(s)
Post-Merger	−	GC Advisors LLC (affiliate of Golub Capital) will continue to serve as the investment adviser of GBDC
Governance	−	All current GBDC officers and directors will remain in their current roles
	−	Joint proxy statement and registration statement declared effective on April 15, 2024
Expected Timing	−	Anticipated closing in CQ2 2024, subject to stockholder approvals (Special Meeting of GBDC stockholders scheduled for May 29, 2024)
		and other customary closing conditions

1. Pro forma as of March 31, 2024.
2. The reduction in incentive fee will become permanent upon merger close. Effective as of January 1, 2024, GC Advisors has agreed to unilaterally waive incentive fees above 15.0% for periods during the pendency of the merger.
3. Paid on March 29, 2024 to stockholders of record date as of March 1, 2024.
4. Special distribution stockholder record dates and payment dates expected to be declared by the Board of Directors at a later time, with the first installment record date to be shortly after merger close.

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Overview of Proposed Merger Consideration

GBDC to acquire 100% of GBDC 3 in a stock-for-stock merger, with shares to be exchanged based upon an exchange ratio determined at merger close that allows for potential NAV per share accretion at GBDC while valuing GBDC 3 at a potential premium to NAV

GBDC Price-to-NAV at Merger Close

Applicable Exchange Ratio Formula

Scenario #1:	GBDC P/NAV <100%	Exchange Ratio = GBDC 3 NAV Per Share / GBDC NAV Per Share
Scenario #2:	100% < GBDC P/NAV < 106%	Exchange Ratio = (GBDC 3 NAV Per Share x (1 + 50% x (GBDC P/NAV -1)) /
GBDC Market Price1
Scenario #3:	GBDC P/NAV >106%	Exchange Ratio = (GBDC 3 NAV Per Share x (1 + 3%)) / GBDC Market Price1

Illustrative Exchange Ratio Calculations Using GBDC & GBDC 3 NAV Per Share as of March 31, 2024

	Scenario #1	Scenario #2	Scenario #3
GBDC Market Price1	$15.00	$15.50	$16.50
GBDC NAV Per Share	$15.12	$15.12	$15.12
GBDC P/NAV	99.2%	102.5%	109.1%
GBDC 3 NAV Per Share	$14.70	$14.70	$14.70
	$14.70 / $15.12 = 0.9721	($14.70 x (1 + 50% x (102.5% -1)) /	($14.70 x (1 + 3.0%)) / $16.50 = 0.9176
	$15.50 = 0.9602
Exchange Ratio	Each GBDC 3 stockholder to receive	Each GBDC 3 stockholder to receive
Each GBDC 3 stockholder to receive
	0.9721 shares of GBDC per GBDC 3 share	0.9176 shares of GBDC per GBDC 3 share
	0.9602 shares of GBDC per GBDC 3 share

Note: Financial data as of March 31, 2024.

1. Represents the price of GBDC Common Stock on the Nasdaq measured on either the day prior to Merger close, if the Nasdaq is closed, the most recent trading day.

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Transaction Rationale

Increased Scale and Liquidity

• GBDC would be the 5th largest externally managed, publicly traded BDC by assets1
• $8.1 billion investment portfolio across 367 portfolio company investments with an average investment size of <0.30%, top ten investments represent <15% of total investment portfolio2
• Larger BDCs generally have greater stock liquidity and wider investor bases

Acquisition of a Like, Diversified Portfolio of Assets

Improved Access to Long-Term,Low-Cost, Flexible Debt Capital

Immediate Net Investment Income ("NII") Accretion and Long-Term Potential for Additional Accretion

Opportunity for NAV Accretion

Potential for Operational Synergies

• Over 99% of GBDC 3's portfolio company investments overlap with those of GBDC2
• GBDC's investment strategy will remain consistent with a focus on first lien, senior secured loans to resilient companies with partnership-oriented private equity sponsors across a range of industries
• The increased scale of the combined company may enable better access to wider array of debt funding solutions and potential borrowing cost reductions
• Larger BDCs have historically issued in the institutional bond market at tighter coupons given greater scale and ability to drive improved liquidity in bond tranches
• Fee structure amendment provides for NII per share accretion immediately (including during the period from merger announcement through merger close)3
• Opportunity to deploy incremental leverage capacity post merger
• Contemplated merger consideration structure provides for NAV accretion if GBDC trades at a premium to NAV at merger close
• In 2019, GBDC and Golub Capital Investment Corporation ("GCIC") closed on the only premium-to-NAV merger precedent in the BDC sector and delivered GBDC NAV accretion
• Combined company is expected to realize annual synergies of approximately ~$1.2 million from duplicative expenses

1. Pro forma as of December 31, 2023.
2. Pro forma as of March 31, 2024.
3. Effective at merger announcement but permanency is subject to closing of the merger.

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GBDC 3 Overview

• Commenced operations October 2, 2017
• Managed by GC Advisors, an affiliate of Golub Capital
• $1.4 billion in investor capital subscriptions1, primarily from institutional investors including marquee pension funds, insurance companies, endowments and foundations
• Intent from inception to seek a liquidity event and to use commercially reasonable efforts to wind down if no liquidity event occurred within six years of the initial closing (to the extent consistent with its fiduciary duties)
• • Stockholders approved an extension of the investment period in October 2023 by two years to October 2025
• Approximately $2.7 billion investment portfolio focused on floating rate, first lien senior secured loans to middle market companies controlled by private equity sponsors; well diversified with 319 portfolio company investments and an average position size of 0.3%1
• Solid performance to date with an average quarterly return on equity of 9.2%2 and an investor internal rate of return since inception of 9.3%3
• Strong credit results. Net realized and unrealized gains on investments for 20 out of 26 quarters since inception. Over 90% of portfolio is performing at or above expectations and only four portfolio company investments are on non-accrual as of March 31, 20241,4

Golub Capital BDC 3, Inc. Quarterly Returns on Equity While Private

(Net of Management Fees, Incentive Fees and all other Expenses)

									8.3%
1.8%	3.1%	3.1%	2.7%	2.3%	2.1%	2.5%	3.0%	2.4%	3.5%	3.1%	3.5%	2.5%	2.2%	2.6%	2.5%	0.7%	1.0%	2.5%	2.8%	3.0%	3.6%	3.6%	Avg.
															0.4%						2.3%

Dec- Mar- Jun-	Sep- Dec- Mar-	Jun-	Sep-		(8.7%)		Sep- Dec- Mar-	Jun-	Sep- Dec- Mar-	Jun-	Sep- Dec- Mar-	Jun-	Sep- Dec- Mar-
Dec- Mar- Jun-
17	18	18	18	18	19	19	19	19	20	20	20	20	21	21	21	21	22	22	22	22	23	23	23	23	24

Note: Past performance does not guarantee future results. Investments are subject to risk of loss.

1. As of March 31, 2024.
2. Represents annualized average quarterly return on equity since inception. Return on equity calculations are based on the daily weighted average of total net assets during the individual quarters.
3. The 9.3% Internal rate of return ("IRR") on NAV is calculated at the fund level using beginning of period NAV, capital share issuances during the period, distributions paid or payable during the period, and ending period NAV. Period beginning August 1, 2017 and ending March 31, 2024. The first investment in GBDC 3 took place on August 1, 2017. These returns do not represent an actual return to any investor in GBDC 3.
4. Refers to investments with GC Advisors' internal performance ratings of 4 or 5. Our internal performance ratings do not constitute any rating of investments by a nationally recognized statistical rating organization or represent or reflect any third-party assessment of any of our investments.

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Combination of GBDC and GBDC 3 Creates the Fifth Largest Externally Managed, Publicly Traded BDC in the Market

GBDC (Pro Forma) will have $8.5 billion in combined total assets, making it the 5th largest externally-managed and publicly traded BDC in the market, and one of the two largest publicly traded BDCs with >90% of its investment portfolio oriented towards 1st lien, senior secured lending

Largest Externally-Managed and Publicly Traded BDCs by Total Assets

($ in Billions)

$25																$23.8
$20										+$2.8 billion
										in total
											assets				$15.5
$15														$13.5
$10													$10.1
										$7.8	$8.5
										$5.7
$5	$2.0	$2.5	$2.5	$2.5	$2.7	$3.2	$3.3	$3.3	$3.5
$1.9
$0
CGBD	CION	BCSF	MFIC	SLRC	BBDC	NMFC	OCSL	TSLX	GSBD	GBDC	PSEC	GBDC	BXSL	OBDC	FSK	ARCC
												(Pro
												Forma)

1st Lien, Senior Secured Investment Portfolio Orientation1:

71%

85%

64%

89%

98%

67%

56%

78%

91%

95%

94%

59%

94%

98%

68%

58%

44%

Note: The BDC peer group utilized by Golub Capital is the 15 largest publicly traded, externally managed BDCs by total balance sheet assets, excluding GBDC, as of December 31, 2023. Golub Capital has selected this group of BDCs for comparison because the Firm believes that the group represents companies that have a similar structure and size as GBDC. Numbers may not sum due to rounding.

1. Represents percentage of total investment portfolio allocated to first lien debt investments based upon fair value as of December 31, 2023. Excludes senior loan fund and first lien oriented joint venture investments, where applicable.

Source: S&P Capital IQ and SEC filings.

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Larger BDCs Generally Have Improved Trading Liquidity

Market Capitalization and Average Daily Trading Volume of Largest Externally-Managed and Publicly Traded BDCs

($ in Millions)

Market	30-Day Average Daily
Capitalization	Trading Volume

$12,000	$80.0
$10,000	$70.0
	$60.0
$8,000	$50.0
$6,000	$40.0
$4,000	$30.0
	$20.0
$2,000	$10.0
$0	$0.0

ARCC OBDC FSK BXSL GBDC GBDC PSEC TSLX OCSL GSBD NMFC BCSF BBDC MFIC SLRC CGBD CION (Pro

Forma) 1

Note: The BDC peer group utilized by Golub Capital is the 15 largest publicly traded, externally managed BDCs by total balance sheet assets, excluding GBDC, as of September 30, 2023. Golub Capital has selected this group of BDCs for comparison because the Firm believes that the group represents companies that have a similar structure and size as GBDC.

Note: Market data as of January 16, 2024.

1. GBDC (Pro Forma) market capitalization assumes application of GBDC's P/NAV premium (as of January 16, 2024) to GBDC 3's NAV as of September 30, 2023; does not reflect merger adjustments. Source: S&P Capital IQ.

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Potential for Continued Improvement in Trading Liquidity

GBDC Market Capitalization and Average Daily Trading Volume Pre- and Post-Merger Close

($ in Millions)

Market	1-Year Average Daily
Capitalization	Trading Volume

$5,000

$4,500

$4,000

$3,500

$3,000

$3,982

$25

$20

$15

$2,500

$2,000

$1,500

$1,000

$500

$0

$1,137

$3.5

210%

Increase

$2,478	$2,557

$10.9

$9.2

Potential for Meaningful Increase

$10

$5

$0

Pre-GCIC Merger Close	Post-GCIC Merger Close	Pre-GBDC 3 Merger 3	Post-GBDC 3 Merger 4
(September 16, 2019)1	(September 16, 2019) 2

1. Market capitalization as of market close on September 16, 2019, and 1-year average daily trading volume for the measurement period 9/17/2018 - 9/16/2019.
2. Market capitalization as of market close on September 17, 2019, and 1-year average daily trading volume for the measurement period 9/17/2019 - 9/16/2020.
3. Market capitalization as of market close on January 16, 2024, and 1-year average daily trading volume for the measurement period 1/17/2023 - 1/16/2024.
4. GBDC (Pro Forma) market capitalization assumes application of GBDC's P/NAV premium (as of January 16, 2024) to GBDC 3's NAV as of September 30, 2023; does not reflect merger adjustments. Source: S&P Capital IQ.

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