of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Entry into a Material Definitive Agreement. On February 24, 2026, GCT Semiconductor, Inc., a subsidiary of GCT Semiconductor Holding, Inc. (the “Company”), entered into Amendment No. 1 (the “Amendment”) to that certain Convertible Promissory Note, dated February 26, 2024 (the “Original Note” and, as amended by the Amendment, the “Note”) with a strategic investor (the “Holder”). The Amendment modifies certain terms of the Original Note, including the extension of the maturity date of the Note…

of this Current Report on Form 8-K relating to the issuance of the Convertible Notes and the Company’s obligations thereunder is incorporated herein by reference. The Company incurred the obligations under the Convertible Notes upon execution of the Purchase Agreement on December 15, 2025. Cautionary Note Regarding Forward-Looking Statements Statements made in this Current Report on Form 8-K that are not descriptions of historical facts are forward-looking statements within the meaning of the…

Creation of a Direct Financial Obligation. The information set forth under

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Creation of a Direct Financial Obligation or an Obligation Under an Off-Balance Sheet Arrangement of a Registrant. The information set forth above under

Entry into a Material Definitive Agreement. September Loan Agreement On September 10, 2025, GCT Research, Inc. (“Borrower”), a wholly owned subsidiary of GCT Semiconductor Holding, Inc. (the “Company”) entered into a Loan Agreement (the “September Loan Agreement”) with Anapass, Inc. (the “Lender”). The September Loan Agreement provides for a term loan facility of an aggregate principal amount of up to ₩15.0 billion South Korean Won (or approximately USD $10.7 million) (the “September Loan”).…

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Entry into a Material Definitive Agreement. On May 15, 2025, GCT Semiconductor Holding, Inc., a Delaware corporation (the “Company”), entered into securities purchase agreements (the “Purchase Agreement”) with certain institutional investors (the “Purchasers”), pursuant to which the Company agreed to issue and sell to the Purchasers in a registered direct offering (the “Offering”) an aggregate of 7,006,370 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (the “…

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Entry into a Material Definitive Agreement. January Loan Agreement On January 24, 2025, GCT Research, Inc. (“Borrower”), a wholly owned subsidiary of GCT Semiconductor Holding, Inc. (the “Company”) entered into a Loan Agreement (the “January Loan Agreement”) with Kyeongho Lee, the Chairman of the Board of the Company (the “Lender”). The January Loan Agreement provides for a term loan facility of an aggregate principal amount of up to ₩6.5 billion South Korean Won (or USD $4,522,998) (the “Jan…

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Unregistered Sales of Equity Securities. The information contained in

Entry into a Material Definitive Agreement. Private Placement Transaction On September 26, 2024, GCT Semiconductor Holding, Inc., a Delaware corporation (the “Company”), entered into a securities purchase agreement (the “Purchase Agreement”) with Anapass, Inc. (the “Purchaser”), pursuant to which the Company shall issue and sell to the Purchaser in a private placement (the “Transaction”) 741,603 shares of common stock of the Company, par value $0.0001 per share (the “Common Stock”) at a purch…

The filing details the approval and terms of a retention plan for executive officers, which is not directly related to any management change.

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Other Events. On July 10, 2024, GCT Semiconductor Holding, Inc. issued a press release announcing a collaboration with Kyocera Corporation to develop a 5G reference platform for customer premise equipment (CPE) and fixed wireless access (FWA) devices. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

of this Current Report, including Exhibit 99.1 attached hereto, shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.

Entry into a Material Definitive Agreement. On April 23, 2024, GCT Semiconductor Holding, Inc. (the “Company”) entered into a Common Stock Purchase Agreement (the “Purchase Agreement”) and a related Registration Rights Agreement (the “Registration Rights Agreement”) with B. Riley Principal Capital II, LLC (“B. Riley Principal Capital II”). Upon the terms and subject to the satisfaction of the conditions set forth in the Purchase Agreement, the Company will have the right, in its sole discreti…

in its entirety. The securities that have been or may be issued under the Purchase Agreement are being offered and sold by the Company in a transaction exempt from registration under Securities Act of 1933, as amended (the “Securities Act”), in reliance on Section 4(a)(2) thereof. B. Riley Principal Capital II represented to the Company in the Purchase Agreement that it is an “accredited investor,” as defined in Regulation D, and is acquiring the securities under the Purchase Agreement for it…

Changes in Registrant’s Certifying Accountants. On April 4, 2023, the Audit Committee of the Board of Directors of GCT Semiconductor Holding, Inc., (f/k/a Concord Acquisition Corp III) (the “Company”) approved the engagement of BPM LLP (“BPM”) as the Company’s independent registered public accounting firm to audit the Company’s consolidated financial statements for the fiscal year ended December 31, 2024, effective immediately. BPM served as the independent registered public accounting firm o…