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Exhibit 99.1 FOR IMMEDIATE RELEASE : Golub Capital BDC , Inc. Announces Fiscal Year 2021 Second Quarter Financial Results and Declares Fiscal Year 2021 Third Quarter Distribution of $ 0.29 Per Share NEW YORK , NY , May 10 , 2021 - Golub Capital BDC , Inc. , a business development company ( Nasdaq : GBDC ) , today announced its financial results for its second fiscal quarter ended March 31 , 2021 . Except where the context suggests otherwise , the terms “ we , ” “ us , ” “ our , " and " Company " refer to Golub Capital BDC , Inc. and its consolidated subsidiaries . " GC Advisors " refers to GC Advisors LLC , our investment adviser . SELECTED FINANCIAL HIGHLIGHTS ( in thousands , expect per share data ) Investment portfolio , at fair value Total assets Net asset value per share March 31 , 2021 $ $ $ 4,395,261 $ 4,605,288 $ 14.86 $ December 31 , 2020 4,507,218 4,802,568 14.60 Net investment income per share Amortization of purchase premium per share Adjusted net investment income per share¹ Quarter Ended March 31 , 2021 December 31 , 2020 $ $ 0.24 $ 0.05 $ 0.23 0.06 $ 0.29 $ 0.29 Net realized / unrealized gain / ( loss ) per share $ 0.31 $ 0.33 Reversal of realized / unrealized loss resulting from the amortization of the purchase premium per share Adjusted net realized / unrealized gain / ( loss ) per share¹ $ ( 0.05 ) $ ( 0.06 ) $ 0.26 $ 0.27 Earnings / ( loss ) per share Adjusted earnings / ( loss ) per share¹ $ 0.55 $ 0.56 $ 0.55 $ 0.56 Net asset value per share Distributions paid per share $ $ 0.29 14.86 $ $ 14.60 0.29 1 On September 16 , 2019 , the Company completed its acquisition of Golub Capital Investment Corporation ( " GCIC " ) . The merger was accounted for under the asset acquisition method of accounting in accordance with Accounting Standards Codification 805-50 , Business Combinations - Related Issues . Under asset acquisition accounting , where the consideration paid to GCIC's stockholders exceeded the relative fair values of the assets acquired , the premium paid by the Company was allocated to the cost of the GCIC assets acquired by the Company pro - rata based on their relative fair value . Immediately following the acquisition of GCIC , the Company recorded its assets at their respective fair values and , as a result , the purchase premium allocated to the cost basis of the GCIC assets acquired was immediately recognized as unrealized depreciation on the Company's Consolidated Statement of Operations . The purchase premium allocated to investments in loan securities acquired from GCIC will amortize over the life of the loans through interest income with a corresponding reversal of the unrealized depreciation on such loans acquired through their ultimate disposition . The purchase premium allocated to investments in equity securities will not amortize over the life of the equity securities through interest income and , assuming no subsequent change to the fair value of the GCIC equity securities acquired and disposition of such equity securities at fair value , the Company will recognize a realized loss with a corresponding reversal of the unrealized depreciation upon disposition of the GCIC equity securities acquired . As a supplement to U.S. generally accepted accounting principles ( " GAAP " ) financial measures , the Company is providing the following non - GAAP financial measures that it believes are useful for the reasons described below : " Adjusted Net Investment Income " and " Adjusted Net Investment Income Per Share " - excludes the amortization of the purchase premium and the accrual for the capital gain incentive fee required under GAAP ( including the portion of such accrual that is not payable under the Company's investment advisory agreement ) from net investment income calculated in accordance with GAAP . " Adjusted Net Realized and Unrealized Gain / ( Loss ) " and " Adjusted Net Realized and Unrealized Gain / ( Loss ) Per Share " - excludes the unrealized loss resulting from the purchase premium write - down and the corresponding reversal of the unrealized loss from the amortization of the premium from the determination of realized and unrealized gain / ( loss ) in accordance with GAAP . " Adjusted Net Income / ( Loss ) " and " Adjusted Earnings / ( Loss ) Per Share " - calculates net income and earnings per share based on Adjusted Net Investment Income and Adjusted Net Realized and Unrealized Gain / ( Loss ) . " Adjusted earnings per share " also excludes the impact of the retroactive adjustment to the weighted average shares calculation due to the bonus element of the rights offering and the resulting impact on earnings per share . The Company believes that excluding the financial impact of the purchase premium write down in the above non - GAAP financial measures is useful for investors as it is a non - cash expense / loss resulting from the acquisition of GCIC and is one method the Company uses to measure its financial condition and results of operations . In addition , the Company believes excluding the accrual of the capital gain incentive fee in the above non - GAAP financial measures is useful as it includes the portion of such accrual that is not contractually payable under the terms of the Company's investment advisory agreement with GC Advisors . Finally , the Company believes excluding the impact of the retroactive adjustment to the weighted average shares calculation due to the bonus element of the rights offering and the resulting impact on per share data is useful for investors as it presents per share financial data that is consistent with what was previously reported .