N-2	6 Months Ended
Mar. 31, 2023
Cover [Abstract]
Entity Central Index Key	0001476765
Amendment Flag	false
Securities Act File Number	814-00794
Document Type	10-Q
Entity Registrant Name	Golub Capital BDC, Inc.
Entity Address, Address Line One	200 Park Avenue
Entity Address, Address Line Two	25th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10166
City Area Code	212
Local Phone Number	750-6060
Entity Emerging Growth Company	false
General Description of Registrant [Abstract]
Investment Objectives and Practices [Text Block]	Our investment objective is to generate current income and capital appreciation by investing primarily in one stop (a loan that combines characteristics of traditional first lien senior secured loans and second lien or subordinated loans and that are often referred to by other middle-market lenders as unitranche loans) and other senior secured loans of U.S. middle-market companies. We also selectively invest in second lien and subordinated loans of, and warrants and minority equity securities in U.S. middle-market companies. We intend to achieve our investment objective by (1) accessing the established loan origination channels developed by Golub Capital, a leading lender to U.S. middle-market companies with over $60.0 billion in capital under management as of January 1, 2023, (2) selecting investments within our core middle-market company focus, (3) partnering with experienced private equity firms, or sponsors, in many cases with whom Golub Capital has invested alongside in the past, (4) implementing the disciplined underwriting standards of Golub Capital and (5) drawing upon the aggregate experience and resources of Golub Capital.
Risk Factors [Table Text Block]	Item 1A: Risk Factors. You should carefully consider the risk factors set forth below and those described in Part I, Item 1A. Risk Factors in our Annual Report on Form 10-K for the year ended September 30, 2022, together with all of the other information included in this report. The risks set out below and in our Annual Report on Form 10-K for the fiscal year ended September 30, 2022 are not the only risks we face. Additional risks and uncertainties not presently known to us or not presently deemed material by us could also impair our operations and performance. If any of these events occur, our business, financial condition, results of operations and cash flows could be materially and adversely affected. In such case, our net asset value and the trading price of our common stock could decline, and you could lose all or part of your investment. The risk factors described below and in our Annual Report on Form 10-K for the fiscal year ended September 30, 2022 are the principal risk factors associated with an investment in us as well as those factors generally associated with an investment company with investment objectives, investment policies, capital structure or trading markets similar to ours.
2018 Debt Securitization [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	2018 Debt Securitization
Long Term Debt, Structuring [Text Block]	2018 Debt Securitization: On November 16, 2018, the Company completed a $602,400 term debt securitization (the “2018 Debt Securitization”). The notes offered in the 2018 Debt Securitization (the “2018 Notes”) were issued by the 2018 Issuer, a subsidiary of 2018 CLO Depositor, and are backed by a diversified portfolio of senior secured and second lien loans. The transaction was executed through a private placement of approximately $327,000 of AAA/AAA Class A 2018 Notes, which bear interest at three-month LIBOR plus 1.48%; $61,200 of AA Class B 2018 Notes, which bear interest at three-month LIBOR plus 2.10%; $20,000 of A Class C-1 2018 Notes, which bear interest at three-month LIBOR plus 2.80%; $38,800 of A Class C-2 2018 Notes, which bear interest at three-month LIBOR plus 2.65%; $42,000 of BBB- Class D 2018 Notes, which bear interest at three-month LIBOR plus 2.95%; and $113,400 of Subordinated 2018 Notes which do not bear interest. The Company indirectly retained all of the Class C-2, Class D and Subordinated 2018 Notes. Through January 20, 2023, the 2018 Issuer was permitted to use all principal collections received on the underlying collateral to purchase new collateral under the direction of the Investment Adviser, in its capacity as collateral manager of the 2018 Issuer and in accordance with the Company’s investment strategy, allowing the Company to maintain the initial leverage in the 2018 Debt Securitization. The 2018 Notes are scheduled to mature on January 20, 2031. The Class A, Class B and Class C-1 2018 Notes are included in the March 31, 2023 and September 30, 2022 Consolidated Statements of Financial Condition as debt of the Company. As of March 31, 2023 and September 30, 2022, the Class C-2, Class D and Subordinated 2018 Notes were eliminated in consolidation. As of March 31, 2023 and September 30, 2022, there were 68 and 74 portfolio companies, respectively, with a total fair value of $579,177 and $568,310, respectively, securing the 2018 Notes. The pool of loans in the 2018 Debt Securitization must meet certain requirements, including asset mix and concentration, collateral coverage, term, agency rating, minimum coupon, minimum spread and sector diversity requirements. The interest charged under the 2018 Debt Securitization is based on three-month LIBOR. The three-month LIBOR in effect as of March 31, 2023 based on the last annualized interest rate reset was 4.8%.
2018 GCIC Debt Securitization [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	GCIC 2018 Debt Securitization
Long Term Debt, Structuring [Text Block]	GCIC 2018 Debt Securitization: Effective September 16, 2019, the Company assumed, as a result of the Merger, a $908,195 term debt securitization (the “GCIC 2018 Debt Securitization”). The GCIC 2018 Debt Securitization was originally completed on December 13, 2018. The notes offered in the GCIC 2018 Debt Securitization (the “GCIC 2018 Notes”) were issued by the GCIC 2018 Issuer, a subsidiary of GCIC 2018 CLO Depositor, and are secured by a diversified portfolio of senior secured and second lien loans. The GCIC 2018 Debt Securitization consists of $490,000 of AAA/AAA Class A-1 GCIC 2018 Notes, $38,500 of AAA Class A-2 GCIC 2018 Notes, and $18,000 of AA Class B-1 GCIC 2018 Notes. In partial consideration for the loans transferred to the GCIC 2018 Issuer as part of the GCIC 2018 Debt Securitization, the GCIC 2018 CLO Depositor received and retained $27,000 of Class B-2 GCIC 2018 Notes, $95,000 of Class C GCIC 2018 Notes and $60,000 of Class D GCIC 2018 Notes and $179,695 of Subordinated GCIC 2018 Notes. On December 21, 2020, the Company and the GCIC 2018 Issuer amended the GCIC 2018 Debt Securitization to, among other things, (a) refinance the issued Class A-2 GCIC 2018 Notes issued by the GCIC 2018 Issuer by redeeming in full the $38,500 of Class A-2 GCIC 2018 Notes and issuing new Class A-2-R GCIC 2018 Notes in an aggregate principal amount of $38,500 that bear interest at a rate of 2.498%, which is a decrease from the rate of 4.665% of the Class A-2 GCIC 2018 Notes and (b) provide for a non-called period, during which the Class A-2-R GCIC 2018 Notes cannot be redeemed, from December 21, 2020 to but excluding June 21, 2021. The Class A-1, Class A-2-R and Class B-1 GCIC 2018 Notes are included in the March 31, 2023 and September 30, 2022 Consolidated Statements of Financial Condition as debt of the Company. As of March 31, 2023 and September 30, 2022, the Class B-2, Class C and Class D GCIC 2018 Notes and the Subordinated GCIC 2018 Notes were eliminated in consolidation. Through January 20, 2023, the GCIC 2018 Issuer was permitted to use all principal collections received on the underlying collateral to purchase new collateral under the direction of the Investment Adviser in its capacity as collateral manager of the GCIC 2018 Issuer and in accordance with the Company’s investment strategy, allowing the Company to maintain the initial leverage in the GCIC 2018 Debt Securitization. The GCIC 2018 Notes are scheduled to mature on January 20, 2031, and the Subordinated GCIC 2018 Notes are scheduled to mature on December 13, 2118. Two loan sale agreements govern the GCIC 2018 Debt Securitization. One of the loan sale agreements provided for the sale of assets upon the closing of the GCIC 2018 Debt Securitization to satisfy risk retention requirements. Under the terms of the other loan sale agreement governing the GCIC 2018 Debt Securitization, the Company agreed to directly or indirectly through the GCIC 2018 CLO Depositor sell or contribute certain senior secured and second lien loans (or participation interests therein) to the GCIC 2018 Issuer. As of both March 31, 2023 and September 30, 2022, there were 91 portfolio companies with a total fair value of $885,099 and $885,171, respectively, securing the GCIC 2018 Notes. The pool of loans in the GCIC 2018 Debt Securitization must meet certain requirements, including asset mix and concentration, collateral coverage, term, agency rating, minimum coupon, minimum spread and sector diversity requirements. The interest charged under the GCIC 2018 Debt Securitization is based on three-month LIBOR. The three-month LIBOR in effect as of March 31, 2023 based on the last interest rate reset was 4.8%. The Investment Adviser serves as the collateral manager to the 2018 Issuer and GCIC 2018 Issuer under separate collateral management agreements and receives a fee for providing these services. The total fees payable by the Company under the Investment Advisory Agreement are reduced by an amount equal to the total aggregate fees paid to the Investment Adviser by the 2018 Issuer and the GCIC 2018 Issuer for rendering such collateral management services. As part of the 2018 Debt Securitization and GCIC 2018 Debt Securitization, GBDC entered into, or assumed in the Merger, master loan sale agreements under which GBDC agreed to directly or indirectly sell or contribute certain senior secured and second lien loans (or participation interests therein) to the 2018 Issuer or the GCIC 2018 Issuer, as applicable, and to purchase or otherwise acquire the LLC equity interests in the Subordinated 2018 Notes and the GCIC Subordinated 2018 Notes, as applicable. As of March 31, 2023, the 2018 Notes and the GCIC 2018 Notes (other than the Subordinated 2018 Notes and the GCIC Subordinated 2018 Notes) were the secured obligations of the 2018 Issuer and the GCIC 2018 Issuer, respectively, and indentures governing each of the 2018 Notes and the GCIC 2018 Notes include customary covenants and events of default.
MS Credit Facility II [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	MS Credit Facility II
Long Term Debt, Structuring [Text Block]	MS Credit Facility II: On February 1, 2019, Funding II entered into a credit facility (as amended, the “MS Credit Facility II”) with Morgan Stanley, as the administrative agent, each of the lenders from time to time party thereto, each of the securitization subsidiaries from time to time party thereto, and Wells Fargo Bank, N.A., as collateral agent, account bank and collateral custodian. On September 16, 2022, all amounts outstanding under the MS Credit Facility II were repaid, following which the agreements governing the MS Credit Facility II were terminated. Prior to its termination, the MS Credit Facility II had a borrowing capacity of $75,000 and bore interest at the applicable base rate plus 2.05%. The base rate under the MS Credit Facility II was (i) one-month LIBOR with respect to any advances denominated in U.S. dollars or U.K. pound sterling, (ii) one-month EURIBOR with respect to any advances denominated in euros, and (iii) one-month Canadian Dollar Offered Rate with respect to any advances denominated in Canadian dollars. The scheduled maturity date of the MS Credit Facility II was April 12, 2026. The MS Credit Facility II was subject to a non-usage fee of 0.50% per annum. The MS Credit Facility II was secured by all of the assets held by Funding II. Both the Company and Funding II made customary representations and warranties and were required to comply with various covenants, reporting requirements and other customary requirements for similar credit facilities. The borrowings under the MS Credit Facility II were subject to the leverage restrictions contained in the 1940 Act. As of both March 31, 2023 and September 30, 2022, the Company did not have any outstanding debt under the MS Credit Facility II.
JPM Credit Facility [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	JPM Credit Facility
Long Term Debt, Structuring [Text Block]	JPM Credit Facility: On February 11, 2021, the Company entered into a senior secured revolving credit facility (as amended, the “JPM Credit Facility”) with the Company, as borrower, JPMorgan Chase Bank N.A., as administrative agent and as collateral agent, and the lenders from time to time party thereto which, as of March 31, 2023, allowed the Company to borrow up to $1,487,500 in U.S. dollars and certain agreed upon foreign currencies, subject to leverage and borrowing base restrictions. Through a series of amendments, most recently on March 17, 2023, the Company amended the JPM Credit Facility, to, among other things, extend the maturity date to March 17, 2028, decrease the adjustment to term SOFR for loans using such rate to 0.10% and increase the accordion feature to allow the Company to request, at one or more times, that existing and/or new lenders, at their election provide up to $512,500 of additional commitments. The JPM Credit Facility provides for the issuance of letters of credit in an initial aggregate face amount of up to $23,750, subject to increase or reduction from time to time pursuant to the terms of the JPM Credit Facility. The JPM Credit Facility is secured by a first priority security interest in substantially all of the assets of the Company and certain of the Company’s subsidiaries thereunder. Borrowings under the JPM Credit Facility are subject to compliance with a borrowing base test. Interest under the JPM Credit Facility for (i) loans for which the Company elects the base rate option, (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the aggregate amount of certain outstanding indebtedness of the Company, or (the “Combined Debt Amount,”) is payable at the greater of (a) the prime rate as last quoted by The Wall Street Journal, (b) the sum of (x) the greater of (I) the federal funds effective rate and (II) the overnight bank funding rate plus (y) 0.5%, and (c) one month LIBOR plus 1% per annum or (the “alternate base rate”) plus 0.75% and, (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, the alternate base rate plus 0.875%; and (ii) loans for which the Company elects the Eurocurrency option (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the Combined Debt Amount, is payable at a rate equal to LIBOR plus 1.75% and (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, is payable at a rate equal to LIBOR plus 1.875%. Effective November 19, 2021, interest under the JPM Facility for loans denominated in Pounds Sterling and Swiss Francs (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the Combined Debt Amounts, is payable at a rate equal to one month SONIA plus 1.7826% per annum or one month Swiss Average Overnight Rate (“SARON”) plus 1.6929% per annum, respectively and, (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, is payable at a rate equal to one month SONIA plus 1.9076% per annum or one month SARON plus 1.8179% per annum, respectively. Effective September 13, 2022, interest under the JPM Facility for loans denominated in LIBOR were converted to reference a benchmark rate of term SOFR plus an adjustment of an amount ranging between 0.11448% and 0.42826% (subject to applicable tenor). Effective March 17, 2023, the adjustment to term SOFR was reduced to 0.10%. The Company pays a commitment fee of 0.375% per annum on the daily unused portion of commitments under the JPM Credit Facility. The Company is also required to pay letter of credit participation fees and a fronting fee on the daily amount of any lender’s exposure with respect to any letters of credit issued at the request of the Company under the JPM Credit Facility. The JPM Credit Facility matures on March 17, 2028, with the exception of a $37,500 commitment from one non-extending lender that matures on February 11, 2026, and requires mandatory prepayment of interest and principal upon certain events during the one year amortization period of the facility. As of March 31, 2023 and September 30, 2022, the Company had outstanding debt of $715,362 and $692,592, respectively, and no letters of credit outstanding under the JPM Credit Facility.
2024 Notes [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	2024 Notes
Long Term Debt, Structuring [Text Block]	2024 Notes: On October 2, 2020, the Company issued $400,000 in aggregate principal amount of unsecured notes (the “2024 Notes”), and on October 15, 2021, the Company issued an additional $100,000 in aggregate principal amount of 2024 Notes under the same terms of the original issuance. As of both March 31, 2023 and September 30, 2022, the outstanding aggregate principal amount of the 2024 Notes was $500,000. The 2024 Notes bear interest at a rate of 3.375% per year payable semiannually in arrears on April 15 and October 15 of each year, commencing on April 15, 2021. The 2024 Notes mature on April 15, 2024. The 2024 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2024 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities. At any time or from time to time, the Company may redeem some or all of the 2024 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2024 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2024 Notes to be redeemed through March 15, 2024 (the date falling one month prior to the maturity date of the 2024 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 50 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2024 Notes on or after March 15, 2024 (the date falling one month prior to the maturity date of the 2024 Notes), the redemption price for the 2024 Notes will be equal to 100% of the principal amount of the 2024 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2024 Notes.
2026 Notes [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	2026 Notes
Long Term Debt, Structuring [Text Block]	2026 Notes: On February 24, 2021, the Company issued $400,000 in aggregate principal amount of unsecured notes (the “2026 Notes”) and on October 13, 2021, the Company issued an additional $200,000 aggregate principal amount of 2026 Notes under the same terms as the original issuance. As of both March 31, 2023 and September 30, 2022, outstanding aggregate principal amount of the 2026 Notes was $600,000. The 2026 Notes bear interest at a rate of 2.500% per year payable semiannually in arrears on February 24 and August 24 of each year, commencing on August 24, 2021. The 2026 Notes mature on August 24, 2026. The 2026 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2026 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities. At any time or from time to time, the Company may redeem some or all of the 2026 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2026 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2026 Notes to be redeemed through July 24, 2026 (the date falling one month prior to the maturity date of the 2026 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 30 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2026 Notes on or after July 24, 2026 (the date falling one month prior to the maturity date of the 2026 Notes), the redemption price for the 2026 Notes will be equal to 100% of the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2026 Notes.
2027 Notes [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	2027 Notes
Long Term Debt, Structuring [Text Block]	2027 Notes: On August 3, 2021, the Company issued $350,000 in aggregate principal amount of unsecured notes (the “2027 Notes”). As of both March 31, 2023 and September 30, 2022, outstanding aggregate principal amount of the 2027 Notes was $350,000. The 2027 Notes bear interest at a rate of 2.050% per year payable semi-annually in arrears on February 15 and August 15 of each year, commencing on February 15, 2022. The 2027 Notes mature on February 15, 2027. The 2027 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2027 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities. At any time or from time to time, the Company may redeem some or all of the 2027 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2027 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2027 Notes to be redeemed through January 15, 2027 (the date falling one month prior to the maturity date of the 2027 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 25 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2027 Notes on or after January 15, 2027 (the date falling one month prior to the maturity date of the 2027 Notes), the redemption price for the 2027 Notes will be equal to 100% of the principal amount of the 2027 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2027 Notes.
Adviser Revolver [Member]
Capital Stock, Long-Term Debt, and Other Securities [Abstract]
Long Term Debt, Title [Text Block]	Adviser Revolver
Long Term Debt, Structuring [Text Block]	Adviser Revolver: The Company has entered into the Adviser Revolver with the Investment Adviser pursuant to which, as of each of March 31, 2023 and September 30, 2022, the Company was permitted to borrow up to $100,000 and which had a maturity date of June 21, 2022. The Adviser Revolver bears an interest rate equal to the short-term Applicable Federal Rate (“AFR”). The short-term AFR as of March 31, 2023 was 4.4%. On June 15, 2022, the Company amended the revolving loan agreement to extend the maturity date to June 15, 2025. As of both March 31, 2023 and September 30, 2022, the Company had no outstanding debt under the Adviser Revolver.

N-2

6 Months Ended

Mar. 31, 2023

Entity Central Index Key

0001476765

Amendment Flag

false

Securities Act File Number

814-00794

Document Type

10-Q

Entity Registrant Name

Golub Capital BDC, Inc.

Entity Address, Address Line One

200 Park Avenue

Entity Address, Address Line Two

25th Floor

Entity Address, City or Town

New York

Entity Address, State or Province

Entity Address, Postal Zip Code

10166

City Area Code

212

Local Phone Number

750-6060

Entity Emerging Growth Company

false

General Description of Registrant [Abstract]

Investment Objectives and Practices [Text Block]

Our investment objective is to generate current income and capital appreciation by investing primarily in one stop (a loan that combines characteristics of traditional first lien senior secured loans and second lien or subordinated loans and that are often referred to by other middle-market lenders as unitranche loans) and other senior secured loans of U.S. middle-market companies. We also selectively invest in second lien and subordinated loans of, and warrants and minority equity securities in U.S. middle-market companies. We intend to achieve our investment objective by (1) accessing the established loan origination channels developed by Golub Capital, a leading lender to U.S. middle-market companies with over $60.0 billion in capital under management as of January 1, 2023, (2) selecting investments within our core middle-market company focus, (3) partnering with experienced private equity firms, or sponsors, in many cases with whom Golub Capital has invested alongside in the past, (4) implementing the disciplined underwriting standards of Golub Capital and (5) drawing upon the aggregate experience and resources of Golub Capital.

Risk Factors [Table Text Block]

Item 1A: Risk Factors.

You should carefully consider the risk factors set forth below and those described in Part I, Item 1A. Risk Factors in our Annual Report on Form 10-K for the year ended September 30, 2022, together with all of the other information included in this report. The risks set out below and in our Annual Report on Form 10-K for the fiscal year ended September 30, 2022 are not the only risks we face. Additional risks and uncertainties not presently known to us or not presently deemed material by us could also impair our operations and performance. If any of these events occur, our business, financial condition, results of operations and cash flows could be materially and adversely affected. In such case, our net asset value and the trading price of our common stock could decline, and you could lose all or part of your investment. The risk factors described below and in our Annual Report on Form 10-K for the fiscal year ended September 30, 2022 are the principal risk factors associated with an investment in us as well as those factors generally associated with an investment company with investment objectives, investment policies, capital structure or trading markets similar to

ours.

2018 Debt Securitization [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

2018 Debt Securitization

Long Term Debt, Structuring [Text Block]

2018 Debt Securitization: On November 16, 2018, the Company completed a $602,400 term debt securitization (the “2018 Debt Securitization”). The notes offered in the 2018 Debt Securitization (the “2018 Notes”) were issued by the 2018 Issuer, a subsidiary of 2018 CLO Depositor, and are backed by a diversified portfolio of senior secured and second lien loans. The transaction was executed through a private placement of approximately $327,000 of AAA/AAA Class A 2018 Notes, which bear interest at three-month LIBOR plus 1.48%; $61,200 of AA Class B 2018 Notes, which bear interest at three-month LIBOR plus 2.10%; $20,000 of A Class C-1 2018 Notes, which bear interest at three-month LIBOR plus 2.80%; $38,800 of A Class C-2 2018 Notes, which bear interest at three-month LIBOR plus 2.65%; $42,000 of BBB- Class D 2018 Notes, which bear interest at three-month LIBOR plus 2.95%; and $113,400 of Subordinated 2018 Notes which do not bear interest. The Company indirectly retained all of the Class C-2, Class D and Subordinated 2018 Notes. Through January 20, 2023, the 2018 Issuer was permitted to use all principal collections received on the underlying collateral to purchase new collateral under the direction of the Investment Adviser, in its capacity as collateral manager of the 2018 Issuer and in accordance with the Company’s investment strategy, allowing the Company to maintain the initial leverage in the 2018 Debt Securitization. The 2018 Notes are scheduled to mature on January 20, 2031. The Class A, Class B and Class C-1 2018 Notes are included in the March 31, 2023 and September 30, 2022 Consolidated Statements of Financial Condition as debt of the Company. As of March 31, 2023 and September 30, 2022, the Class C-2, Class D and Subordinated 2018 Notes were eliminated in consolidation.

As of March 31, 2023 and September 30, 2022, there were 68 and 74 portfolio companies, respectively, with a total fair value of $579,177 and $568,310, respectively, securing the 2018 Notes. The pool of loans in the 2018 Debt Securitization must meet certain requirements, including asset mix and concentration, collateral coverage, term, agency rating, minimum coupon, minimum spread and sector diversity requirements.

The interest charged under the 2018 Debt Securitization is based on three-month LIBOR. The three-month LIBOR in effect as of March 31, 2023 based on the last annualized interest rate reset was 4.8%.

2018 GCIC Debt Securitization [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

GCIC 2018 Debt Securitization

Long Term Debt, Structuring [Text Block]

GCIC 2018 Debt Securitization: Effective September 16, 2019, the Company assumed, as a result of the Merger, a $908,195 term debt securitization (the “GCIC 2018 Debt Securitization”). The GCIC 2018 Debt Securitization was originally completed on December 13, 2018. The notes offered in the GCIC 2018 Debt Securitization (the “GCIC 2018 Notes”) were issued by the GCIC 2018 Issuer, a subsidiary of GCIC 2018 CLO Depositor, and are secured by a diversified portfolio of senior secured and second lien loans. The GCIC 2018 Debt Securitization consists of $490,000 of AAA/AAA Class A-1 GCIC 2018 Notes, $38,500 of AAA Class A-2 GCIC 2018 Notes, and $18,000 of AA Class B-1 GCIC 2018 Notes. In partial consideration for the loans transferred to the GCIC 2018 Issuer as part of the GCIC 2018 Debt Securitization, the GCIC 2018 CLO Depositor received and retained $27,000 of Class B-2 GCIC 2018 Notes, $95,000 of Class C GCIC 2018 Notes and $60,000 of Class D GCIC 2018 Notes and $179,695 of Subordinated GCIC 2018 Notes. On December 21, 2020, the Company and the GCIC 2018 Issuer amended the GCIC 2018 Debt Securitization to, among other things, (a) refinance the issued Class A-2 GCIC 2018 Notes issued by the GCIC 2018 Issuer by redeeming in full the $38,500 of Class A-2 GCIC 2018 Notes and issuing new Class A-2-R GCIC 2018 Notes in an aggregate principal amount of $38,500 that bear interest at a rate of 2.498%, which is a decrease from the rate of 4.665% of the Class A-2 GCIC 2018 Notes and (b) provide for a non-called period, during which the Class A-2-R GCIC 2018 Notes cannot be redeemed, from December 21, 2020 to but excluding June 21, 2021. The Class A-1, Class A-2-R and Class B-1 GCIC 2018 Notes are included in the March 31, 2023 and September 30, 2022 Consolidated Statements of Financial Condition as debt of the Company. As of March 31, 2023 and September 30, 2022, the Class B-2, Class C and Class D GCIC 2018 Notes and the Subordinated GCIC 2018 Notes were eliminated in consolidation.

Through January 20, 2023, the GCIC 2018 Issuer was permitted to use all principal collections received on the underlying collateral to purchase new collateral under the direction of the Investment Adviser in its capacity as collateral manager of the GCIC 2018 Issuer and in accordance with the Company’s investment strategy, allowing the Company to maintain the initial leverage in the GCIC 2018 Debt Securitization. The GCIC 2018 Notes are scheduled to mature on January 20, 2031, and the Subordinated GCIC 2018 Notes are scheduled to mature on December 13, 2118.

Two loan sale agreements govern the GCIC 2018 Debt Securitization. One of the loan sale agreements provided for the sale of assets upon the closing of the GCIC 2018 Debt Securitization to satisfy risk retention requirements. Under the terms of the other loan sale agreement governing the GCIC 2018 Debt Securitization, the Company agreed to directly or indirectly through the GCIC 2018 CLO Depositor sell or contribute certain senior secured and second lien loans (or participation interests therein) to the GCIC 2018 Issuer.

As of both March 31, 2023 and September 30, 2022, there were 91 portfolio companies with a total fair value of $885,099 and $885,171, respectively, securing the GCIC 2018 Notes. The pool of loans in the GCIC 2018 Debt Securitization must meet certain requirements, including asset mix and concentration, collateral coverage, term, agency rating, minimum coupon, minimum spread and sector diversity requirements.

The interest charged under the GCIC 2018 Debt Securitization is based on three-month LIBOR. The three-month LIBOR in effect as of March 31, 2023 based on the last interest rate reset was 4.8%.

The Investment Adviser serves as the collateral manager to the 2018 Issuer and GCIC 2018 Issuer under separate collateral management agreements and receives a fee for providing these services. The total fees payable by the Company under the Investment Advisory Agreement are reduced by an amount equal to the total aggregate fees paid to the Investment Adviser by the 2018 Issuer and the GCIC 2018 Issuer for rendering such collateral management services.

As part of the 2018 Debt Securitization and GCIC 2018 Debt Securitization, GBDC entered into, or assumed in the Merger, master loan sale agreements under which GBDC agreed to directly or indirectly sell or contribute certain senior secured and second lien loans (or participation interests therein) to the 2018 Issuer or the GCIC 2018 Issuer, as applicable, and to purchase or otherwise acquire the LLC equity interests in the Subordinated 2018 Notes and the GCIC Subordinated 2018 Notes, as applicable. As of March 31, 2023, the 2018 Notes and the GCIC 2018 Notes (other than the Subordinated 2018 Notes and the GCIC Subordinated 2018 Notes) were the secured obligations of the 2018 Issuer and the GCIC 2018 Issuer, respectively, and indentures governing each of the 2018 Notes and the GCIC 2018 Notes include customary covenants and events of default.

MS Credit Facility II [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

MS Credit Facility II

Long Term Debt, Structuring [Text Block]

MS Credit Facility II: On February 1, 2019, Funding II entered into a credit facility (as amended, the “MS Credit Facility II”) with Morgan Stanley, as the administrative agent, each of the lenders from time to time party thereto, each of the securitization subsidiaries from time to time party thereto, and Wells Fargo Bank, N.A., as collateral agent, account bank and collateral custodian. On September 16, 2022, all amounts outstanding under the MS Credit Facility II were repaid, following which the agreements governing the MS Credit Facility II were terminated. Prior to its termination, the MS Credit Facility II had a borrowing capacity of $75,000 and bore interest at the applicable base rate plus 2.05%. The base rate under the MS Credit Facility II was (i) one-month LIBOR with respect to any advances denominated in U.S. dollars or U.K. pound sterling, (ii) one-month EURIBOR with respect to any advances denominated in euros, and (iii) one-month Canadian Dollar Offered Rate with respect to any advances denominated in Canadian dollars. The scheduled maturity date of the MS Credit Facility II was April 12, 2026. The MS Credit Facility II was subject to a non-usage fee of 0.50% per annum.

The MS Credit Facility II was secured by all of the assets held by Funding II. Both the Company and Funding II made customary representations and warranties and were required to comply with various covenants, reporting requirements and other customary requirements for similar credit facilities. The borrowings under the MS Credit Facility II were subject to the leverage restrictions contained in the 1940 Act.

As of both March 31, 2023 and September 30, 2022, the Company did not have any outstanding debt under the MS Credit Facility II.

JPM Credit Facility [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

JPM Credit Facility

Long Term Debt, Structuring [Text Block]

JPM Credit Facility: On February 11, 2021, the Company entered into a senior secured revolving credit facility (as amended, the “JPM Credit Facility”) with the Company, as borrower, JPMorgan Chase Bank N.A., as administrative agent and as collateral agent, and the lenders from time to time party thereto which, as of March 31, 2023, allowed the Company to borrow up to $1,487,500 in U.S. dollars and certain agreed upon foreign currencies, subject to leverage and borrowing base restrictions. Through a series of amendments, most recently on March 17, 2023, the Company amended the JPM Credit Facility, to, among other things, extend the maturity date to March 17, 2028, decrease the adjustment to term SOFR for loans using such rate to 0.10% and increase the accordion feature to allow the Company to request, at one or more times, that existing and/or new lenders, at their election provide up to $512,500 of additional commitments.

The JPM Credit Facility provides for the issuance of letters of credit in an initial aggregate face amount of up to $23,750, subject to increase or reduction from time to time pursuant to the terms of the JPM Credit Facility. The JPM Credit Facility is secured by a first priority security interest in substantially all of the assets of the Company and certain of the Company’s subsidiaries thereunder.

Borrowings under the JPM Credit Facility are subject to compliance with a borrowing base test. Interest under the JPM Credit Facility for (i) loans for which the Company elects the base rate option, (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the aggregate amount of certain outstanding indebtedness of the Company, or (the “Combined Debt Amount,”) is payable at the greater of (a) the prime rate as last quoted by The Wall Street Journal, (b) the sum of (x) the greater of (I) the federal funds effective rate and (II) the overnight bank funding rate plus (y) 0.5%, and (c) one month LIBOR plus 1% per annum or (the “alternate base rate”) plus 0.75% and, (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, the alternate base rate plus 0.875%; and (ii) loans for which the Company elects the Eurocurrency option (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the Combined Debt Amount, is payable at a rate equal to LIBOR plus 1.75% and (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, is payable at a rate equal to LIBOR plus 1.875%. Effective November 19, 2021, interest under the JPM Facility for loans denominated in Pounds Sterling and Swiss Francs (A) if the value of the gross borrowing base is equal to or greater than 1.60 times the Combined Debt Amounts, is payable at a rate equal to one month SONIA plus 1.7826% per annum or one month Swiss Average Overnight Rate (“SARON”) plus 1.6929% per annum, respectively and, (B) if the value of the gross borrowing base is less than 1.60 times the Combined Debt Amount, is payable at a rate equal to one month SONIA plus 1.9076% per annum or one month SARON plus 1.8179% per annum, respectively. Effective September 13, 2022, interest under the JPM Facility for loans denominated in LIBOR were converted to reference a benchmark rate of term SOFR plus an adjustment of an

amount ranging between 0.11448% and 0.42826% (subject to applicable tenor). Effective March 17, 2023, the adjustment to term SOFR was reduced to 0.10%.

The Company pays a commitment fee of 0.375% per annum on the daily unused portion of commitments under the JPM Credit Facility. The Company is also required to pay letter of credit participation fees and a fronting fee on the daily amount of any lender’s exposure with respect to any letters of credit issued at the request of the Company under the JPM Credit Facility. The JPM Credit Facility matures on March 17, 2028, with the exception of a $37,500 commitment from one non-extending lender that matures on February 11, 2026, and requires mandatory prepayment of interest and principal upon certain events during the one year amortization period of the facility.

As of March 31, 2023 and September 30, 2022, the Company had outstanding debt of $715,362 and $692,592, respectively, and no letters of credit outstanding under the JPM Credit Facility.

2024 Notes [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

2024 Notes

Long Term Debt, Structuring [Text Block]

2024 Notes: On October 2, 2020, the Company issued $400,000 in aggregate principal amount of unsecured notes (the “2024 Notes”), and on October 15, 2021, the Company issued an additional $100,000 in aggregate principal amount of 2024 Notes under the same terms of the original issuance. As of both March 31, 2023 and September 30, 2022, the outstanding aggregate principal amount of the 2024 Notes was $500,000. The 2024 Notes bear interest at a rate of 3.375% per year payable semiannually in arrears on April 15 and October 15 of each year, commencing on April 15, 2021. The 2024 Notes mature on April 15, 2024.

The 2024 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2024 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities.

At any time or from time to time, the Company may redeem some or all of the 2024 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2024 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2024 Notes to be redeemed through March 15, 2024 (the date falling one month prior to the maturity date of the 2024 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 50 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2024 Notes on or after March 15, 2024 (the date falling one month prior to the maturity date of the 2024 Notes), the redemption price for the 2024 Notes will be equal to 100% of the principal amount of the 2024 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2024 Notes.

2026 Notes [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

2026 Notes

Long Term Debt, Structuring [Text Block]

2026 Notes: On February 24, 2021, the Company issued $400,000 in aggregate principal amount of unsecured notes (the “2026 Notes”) and on October 13, 2021, the Company issued an additional $200,000 aggregate principal amount of 2026 Notes under the same terms as the original issuance. As of both March 31, 2023 and September 30, 2022, outstanding aggregate principal amount of the 2026 Notes was $600,000. The 2026 Notes bear interest at a rate of 2.500% per year payable semiannually in arrears on February 24 and August 24 of each year, commencing on August 24, 2021. The 2026 Notes mature on August 24, 2026.

The 2026 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2026 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities.

At any time or from time to time, the Company may redeem some or all of the 2026 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2026 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2026 Notes to be redeemed through July 24, 2026 (the date falling one month prior to the maturity date of the 2026 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 30 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2026 Notes on or after July 24, 2026 (the date falling one month prior to the maturity date of the 2026 Notes), the redemption price for the 2026 Notes will be equal to 100% of the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2026 Notes.

2027 Notes [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

2027 Notes

Long Term Debt, Structuring [Text Block]

2027 Notes: On August 3, 2021, the Company issued $350,000 in aggregate principal amount of unsecured notes (the “2027 Notes”). As of both March 31, 2023 and September 30, 2022, outstanding aggregate principal amount of the 2027 Notes was $350,000. The 2027 Notes bear interest at a rate of 2.050% per year payable semi-annually in arrears on February 15 and August 15 of each year, commencing on February 15, 2022. The 2027 Notes mature on February 15, 2027.

The 2027 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of the Company’s future indebtedness or other obligations that are expressly subordinated, or junior, in right of payment to the 2027 Notes; equal in right of payment to the Company’s existing and future indebtedness or other obligations that are not so subordinated or junior; effectively junior to any of the Company’s secured indebtedness or other obligations (including unsecured indebtedness that the Company later secures) to the extent of the value of the assets securing such indebtedness; and structurally junior to all existing and future indebtedness and other obligations (including trade payables) incurred by the Company’s subsidiaries, financing vehicles or similar facilities.

At any time or from time to time, the Company may redeem some or all of the 2027 Notes at a redemption price equal to the greater of (1) 100% of the principal amount of the 2027 Notes to be redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest (exclusive of accrued and unpaid interest to the date of redemption) on the 2027 Notes to be redeemed through January 15, 2027 (the date falling one month prior to the maturity date of the 2027 Notes), discounted to the redemption date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) using the applicable Treasury Rate plus 25 basis points, plus, in each case, accrued and unpaid interest, if any, to, but excluding, the redemption date; provided, however, that if the Company redeems any 2027 Notes on or after January 15, 2027 (the date falling one month prior to the maturity date of the 2027 Notes), the redemption price for the 2027 Notes will be equal to 100% of the principal amount of the 2027 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. No sinking fund is provided for the 2027 Notes.

Adviser Revolver [Member]

Capital Stock, Long-Term Debt, and Other Securities [Abstract]

Long Term Debt, Title [Text Block]

Adviser Revolver

Long Term Debt, Structuring [Text Block]

Adviser Revolver: The Company has entered into the Adviser Revolver with the Investment Adviser pursuant to which, as of each of March 31, 2023 and September 30, 2022, the Company was permitted to borrow up to $100,000 and which had a maturity date of June 21, 2022. The Adviser Revolver bears an interest rate equal to the short-term Applicable Federal Rate (“AFR”). The short-term AFR as of March 31, 2023 was 4.4%. On June 15, 2022, the Company amended the revolving loan agreement to extend the maturity date to June 15, 2025. As of both March 31, 2023 and September 30, 2022, the Company had no outstanding debt under the Adviser Revolver.