GCT Semiconductor Holding, Inc. Debt Disclosure

7. Debt

Convertible Promissory Notes

2024 Convertible Promissory Notes

In February 2024 and March 2024, the Company issued convertible promissory notes to certain investors (the “CVT Investors”), pursuant to which the CVT Investors agreed to lend to the Company an aggregate principal amount of $13.3 million. These notes had maturity dates ranging from November 2026 to March 2027, bore an annual interest rate of 5.0%, and were automatically convertible upon IPO or SPAC transaction. In March 2024, upon the Closing of the Business Combination, an aggregate principal and interest amount of $13.4 million converted into 2,004,535 shares of common stock at a conversion price of $6.67. As of December 31, 2025, none of the notes issued to CVT Investors remain outstanding.

In February 2024, the Company issued a convertible promissory note to a strategic investor for a principal amount of $5.0 million with an original maturity date in February 2026 and bears an annual interest rate of 5.0%. On or after the earlier of (i) six months from the issuance date of the convertible promissory note and (ii) the Closing of the Business Combination, the noteholder may demand that the Company convert all principal and interest due under the convertible promissory note into shares of the Company’s common stock, at a conversion price of $10.00 per share. This note includes customary representations, warranties, and events of default, as well as a covenant relating to the performance of obligations by the Company related to the Company’s 5G activity. In February 2026, the Company executed an amendment to extend the maturity date from February 2026 to February 2028. As of December 31, 2025, the remaining principal and interest amount of $5.5 million was outstanding.

Indigo Convertible Promissory Notes

In December 2025, the Company issued two Indigo Notes, each with a principal amount of $1.0 million, and received gross proceeds of $1.9 million based on the discount upon issuance.

Each Indigo Note was issued at a purchase price equal to 93% of its principal amount. Each Indigo Note matures 24 months from its issuance date and is convertible into the Company’s common stock at any time on or before its maturity date unless redeemed by the Company. The conversion price is 90% of the reference price, which is calculated as the lowest volume-weighted average price (“VWAP”) of the Company’s common stock over the three trading days prior to the submission of a conversion notice by Indigo. The reference price is subject to a floor of 96% of the average VWAP during this three-day period. No interest is payable on the Indigo Notes, and the Company has an optional redemption right beginning 12 months following the issuance of the Indigo Notes. Redemption between 12 and 18 months from issuance carries a premium of 7% on the principal amount redeemed, increasing to 14% if redeemed between 18 months and prior to maturity.

In December 2025, the first Indigo Note was converted into 903,710 shares of our common stock, and the second Indigo Note with a principal amount of $1.0 million remained outstanding as of December 31, 2025.

The Company has elected the fair value option to account for the Indigo Notes, and these instruments are initially and subsequently measured at fair value under ASC 825, with changes in fair value reported separately in the consolidated statements of operations, except for adjustments attributable to instrument-specific credit risk, which are reported in other comprehensive income on the consolidated statements of comprehensive loss. Transaction costs associated with the issuance of the convertible promissory notes are expensed as incurred.

Borrowings Pursuant to Term Loan and Security Agreements

The amounts in South Korean won (“KRW”) presented below were converted into U.S. dollars based on the applicable historical exchange rates.

KEB Hana Bank

In July 2016, the Company entered into an unsecured term loan agreement with KEB Hana Bank, pursuant to which it borrowed 9.0 billion in KRW ($6.7 million), bearing a variable interest rate (initial annual interest rate of 2.6% and annual interest rates ranging between 3.1%-4.0% as of December 31, 2025), paid monthly, and maturing in July 2017. The terms of such unsecured term loan agreement have been extended annually for additional one-year terms since 2017, and the maturity date was July 2024. In April 2024, the Company executed an amendment to extend the maturity date to April 2025 for the principal amount of KRW 1.0 billion ($0.7 million) with an annual interest rate of 3.5%. In July 2024, the Company executed an amendment to extend the maturity date to July 2025 for the principal amount of KRW 8.0 billion ($6.0 million) with an annual interest rate of 4.9%. Anapass, Inc., a related party, provided certificates of deposit as collateral to KEB Hana Bank to secure the Company’s obligations under this loan (see Note 8). In April 2025, the Company executed an amendment to extend the maturity date to April 2026 for the principal amount of KRW 1.0 billion ($0.7 million) with an annual interest rate of 3.1%. In July 2025, the Company executed an amendment to extend the maturity date to July 2026 for the principal amount of KRW 8.0 billion ($5.6 million) with an annual interest rate of 4.0%.

IBK Industrial Bank

In January 2017, the Company entered into a term loan agreement with IBK Industrial Bank, pursuant to which the Company borrowed KRW 9.2 billion ($6.8 million). The term loan has a maturity date in November 2025 and bears an annual interest rate of 4.1%. In June 2025, the Company executed an amendment to change the annual interest rate from 4.1% to 4.0%, effective June 12, 2025. In November 2025, the Company executed an amendment to extend the maturity date to November 2026 and change the annual interest rate from 4.0% to 3.6%.

Note Payable (One Individual Investor)

In June 2021, the Company entered into a note payable agreement with an individual investor, pursuant to which the Company borrowed $1.0 million. The note had a maturity date of June 2024 and bears an annual interest rate of 4.0%. In April 2022, the Company entered into an amendment with this one individual investor to remove the conversion right from the note payable. In June 2024, the Company executed an amendment with the individual investor to extend the maturity date from June 2024 to August 2024. In August 2024, the Company repaid this note.

M-Venture Investment, Inc.

In October 2021, the Company entered into a term loan and security agreement with M-Venture Investment, Inc. pursuant to which the Company borrowed KRW 5.0 billion ($3.7 million) and repaid KRW 0.6 billion ($0.4 million) and KRW 0.4 billion ($0.3 million) in 2021 and 2022, respectively, such that KRW 4.0 billion ($3.0 million) remained outstanding. The term loan bears an annual interest rate of 6.5%. In April 2024, the Company executed an amendment with M-Venture Investment, Inc., pursuant to which the Company repaid KRW 2.0 billion ($1.5 million) in April 2024. In May 2024, the Company repaid the term loan in full.

In April 2022, the Company entered into a term loan and security agreement with M-Venture Investment, Inc., pursuant to which the Company borrowed amounts in two draws of KRW 1.0 billion ($0.7 million) and KRW 5.0 billion ($3.7 million), respectively. The term loan had a maturity date in April 2024, and each respective draw bears an annual interest rate of 6.5% and 8.7%. In April 2024, the Company executed an amendment with M-Venture Investment, Inc., pursuant to which the maturity date for both draws were amended. The maturity date for the principal amount of KRW 1.0 billion ($0.7 million) was extended from April 2024 to June 2024. The maturity date for the principal amount of KRW 5.0 billion ($3.7 million) was extended from April 2024 to July 2024. In July 2024, the Company repaid the loan of KRW 1.0 billion ($0.7 million) and assigned the remaining balance of KRW 5.0 billion ($3.7 million) (“M-Venture Loan”) to Mujin Electronics Co., Ltd. as further discussed below.

Mujin Electronics Co., Ltd.

In July 2024, the Company executed agreement with M-Venture Investment, Inc. and Mujin Electronics Co., Ltd., in which Mujin Electronics Co., Ltd. fully assumed the remaining M-Venture Loan with the same principal amount of KRW 5.0 billion ($3.7 million). The maturity date of assumed loan at the time of the assignment was January 2025, with an annual interest rate of 6.8%. In October 2024, the Company executed an amendment to extend the maturity date to June 2025. In June 2025, the Company executed an amendment to further extend the maturity date to October 2025. In October 2025, the Company executed an amendment to further extend the maturity date to December 2025. In December 2025, the Company executed an amendment to further extend the maturity date to April 2026.

Anapass, Inc., Related Party

In July 2016, the Company entered into a loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 6.0 billion ($4.5 million) in a term loan. Interest-only payments are due monthly at 5.5% per annum and the principal amount of the term loan is due on the maturity date of July 2024. In July 2024, the Company and Anapass, Inc. amended the loan agreement to extend the maturity date from July 2024 to July 2025. The loan is collateralized by the Company’s assets as described under the Assets Pledged as Collateral (see Note 8). In July 2025, the Company entered into an amendment to extend the maturity date from July 2025 to July 2026.

In May 2022, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 3.0 billion ($2.2 million). The term loan had maturity date in May 2024 and bears an annual interest rate of 5.5%. In May 2024, the Company executed an amendment with Anapass, Inc., to extend the maturity date from May 2024 to May 2025. In May 2025, the Company executed an amendment with Anapass, Inc., to extend the maturity date from May 2025 to November 2025. In November 2025, the Company executed an amendment with Anapass, Inc., to extend the maturity date from November 2025 to November 2026 and change the annual interest rate from 5.5% to 7.0%.

In September 2022, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 4.0 billion ($3.0 million). The term loan had maturity date in September 2024 and bears an annual interest rate of 5.5%. In September 2024, the Company executed an amendment with Anapass, Inc., to extend the maturity date from September 2024 to September 2025. In September 2025, the Company executed an amendment with Anapass, Inc., to extend the maturity date from September 2025 to September 2026 and change the annual interest rate from 5.5% to 7.0%.

In December 2024, the Company entered into a new term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 5.0 billion ($3.4 million). The term loan has a maturity date in December 2025 and bears an annual interest rate of 6.5%. In December 2025, the Company executed an amendment to extend the maturity date from December 2025 to December 2026 and change the annual interest rate from 6.5% to 7.0%.

In March 2025, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 4.5 billion ($3.1 million). The term loan has a maturity date in March 2026 and bears an annual interest rate of 6.5%.

In July 2025, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 3.0 billion ($2.1 million). The term loan has a maturity date in July 2026 and bears an annual interest rate of 6.5%.

In August 2025, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 2.0 billion ($1.4 million). The term loan has a maturity date in August 2026 and bears an annual interest rate of 6.5%.

In September 2025, the Company entered into a term loan agreement with Anapass, Inc. pursuant to which the Company borrowed KRW 15.0 billion ($10.7 million). The term loan has a maturity date in September 2026 and bears an annual interest rate of 7.0%.

i Best Investment Co., Ltd

Between 2022 and 2023, the Company entered into multiple term loans and security agreements with i Best Investment Co., Ltd pursuant to which it borrowed principal amounts in six draws with an aggregate principal balance of KRW 14.0 billion ($10.3 million). All of the term loans had a maturity date in June 2024 and bear an annual interest rate of 6.5%. In June 2024, the Company executed an amendment with the i Best Investment Co., Ltd to extend the maturity date from June 2024 to August 2024 for its first draw, fifth draw and sixth draw. In December 2023, the Company made a $0.8 million repayment of the outstanding principal and interest on its second draw. In March 2024, the Company repaid $2.3 million of the outstanding principal and interest amount of its fourth draw. In June 2024, the Company repaid in full the term loans with a principal amount of $1.4 million outstanding on its third draw. In July 2024, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from August 2024 to February 2025 for its first draw, fifth draw and sixth draw. In October 2024, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from February 2025 to May 2025 for its sixth draw.

In February 2025, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from February 2025 to May 2025 for its first draw and fifth draw. In May 2025, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from May 2025 to June 2025 for its first and fifth draw. In May 2025, the Company paid in full the term loans with a principal amount of $1.5 million outstanding on its fifth and sixth draw. In June 2025, the Company made a $0.7 million repayment of the principal amount of its first draw and extended the maturity date from June 2025 to December 2025 for the remaining principal amount of $2.2 million for its first draw. In December 2025, the Company executed an amendment with i Best Investment Co., Ltd. to extend the maturity date from December 2025 to June 2026.

Kyeongho Lee, Related Party

Between 2017 and 2021, the Company entered into multiple promissory note and term loan agreements with Kyeongho Lee pursuant to which the Company borrowed (a) KRW 500.0 million ($0.4 million) and KRW 500.0 million ($0.4 million) in promissory notes, and (b) KRW 1.0 billion ($0.7 million) and KRW 110.0 million ($0.1 million) in term loans. The promissory notes have a maturity date in November 2024 and bear an annual interest rate varying from 7.5% and 9.0%. In March 2024, the Company repaid to Kyeongho Lee the term loan of KRW 1.0 billion ($0.7 million). The outstanding term loan had a maturity date in May 2024 and bears no interest. In May 2024, the Company executed an amendment with Kyeongho Lee to extend the maturity date from May 2024 to November 2024 for its term loan. In November 2024, the Company executed two amendments with Kyeongho Lee to extend the maturity dates of two promissory notes from November 2024 to November 2025, and the maturity date of the term loan from November 2024 to May 2025. In May 2025, the Company executed an amendment with Kyeongho Lee to extend the maturity date of the term loan from May 2025 to August 2025. In August 2025, the Company executed an amendment with Kyeongho Lee to extend the maturity date of the term loan from August 2025 to December 2025. In October 2025, the Company repaid to Kyeongho Lee the term loan of KRW 110.0 million ($0.1 million) initially executed in May 2020. In November 2025, the Company executed an amendment to extend the maturity dates of the two promissory notes from November 2025 to November 2026.

In November 2024, the Company entered into a term loan agreement with Kyeongho Lee pursuant to which the Company borrowed KRW 4.0 billion ($2.9 million) at an annual interest rate of 12%. The term loan had a maturity date in December 2024. In January 2026, the Company partially repaid KRW 1.4 billion ($1.0 million) of the principal amount of the term loan initially executed in November 2024, resulting in KRW 2.6 billion ($1.8 million) remaining outstanding as of the issuance date of these consolidated financial statements. In December 2024, the Company entered into two term loan agreements with Kyeongho Lee pursuant to which the Company borrowed KRW 1.0 billion ($0.7 million) and KRW 2.0 billion ($1.4 million). The term loans have maturity dates in January 2025 and bear an annual interest rate of 12%. In October 2025, the Company repaid to Kyeongho Lee the term loan of KRW 2.0 billion ($1.4 million) initially executed in December 2024. The term loan for KRW 1.0 billion ($0.7 million) remains outstanding as of the issuance date of these consolidated financial statements. In January 2025, the Company entered into a term loan agreement with Kyeongho Lee pursuant to which the Company borrowed KRW 6.5 billion ($4.4 million) with a maturity date in February 2025 and an annual interest rate of 12%, which remains outstanding as of the issuance date of these consolidated financial statements. For the year ended December 31, 2025, the Company incurred penalties of 3% of principal per month on loans in the amount of $2.9 million that are past their maturity dates, calculated daily until the principal and accrued interest are paid, and are presented within interest expense in the consolidated statement of operations. No penalties were incurred for the year ended December 31, 2024. Outstanding penalties payable to Kyeongho Lee as of December 31, 2025 are $2.5 million.