The Company accounts for all leases in accordance with ASC 842 (Note 2). The Company is party to five facility leases in South Africa for office, manufacturing and laboratory space.

A lease for office and laboratory space in Pretoria, South Africa commenced in October 2021 with the initial term set to expire in December 2030. The Company has applied the guidance in ASC 842 and has determined that it should be classified as an operating lease. The Company’s incremental borrowing rate for this lease is 7.5% based on the remaining lease term of the applicable lease. Consequently, a ROU lease asset of $952,521 with a corresponding lease liability of $952,521 based on the present value of the minimum rental payments of such lease was recorded at the inception of the lease.

A lease for additional production space in Pretoria, South Africa commenced in April 2023 with the initial term set to expire in March 2024. Effective February 1, 2024, this lease was amended such that the new term begins on February 1, 2024 and expires in February 2026. Prior to the amendment, the Company had applied the guidance in ASC 842 and determined that this lease was a short-term lease and expensed the monthly payments as incurred. The Company has applied the guidance in ASC 842 to the amended lease and has determined that it should be classified as an operating lease. The Company’s incremental borrowing rate for this lease is 10.6% based on the lease term of the applicable lease. Consequently, a ROU lease asset of $364,458 with a corresponding lease liability of $364,458 based on the present value of the minimum rental payments of such lease was recorded at the inception of the amended lease.

A lease for laboratory space in Pretoria, South Africa commenced in November 2023 with the initial term set to expire in October 2026. The Company has applied the guidance in ASC 842 and has determined that it should be classified as an operating lease. The Company’s incremental borrowing rate for this lease is 13.16% based on the remaining lease term of the applicable lease. Consequently, a ROU lease asset of $70,607 with a corresponding lease liability of $70,607 based on the present value of the minimum rental payments of such lease was recorded at the inception of the lease. Additionally, a lease for office space in Pretoria, South Africa commenced in June 2025 with the initial term set to expire in May 2028. The Company has applied the guidance in ASC 842 and has determined that it should be classified as an operating lease. The Company’s incremental borrowing rate for this lease is 10.79% based on the lease term of the applicable lease. Consequently, a ROU lease asset of $70,607 with a corresponding lease liability of $101,929 based on the present value of the minimum rental payments of such lease was recorded at the inception of the lease

A lease for office and production space in Pretoria, South Africa commenced prior to October 31, 2023 with the initial term set to expire in March 2026. The Company has applied the guidance in ASC 842 and has determined that it should be classified as an operating lease effective on the date of ASP Isotopes' acquisition of 51% of PET Labs. The Company’s incremental borrowing rate is

approximately 12.875% based on the expected remaining lease term of the applicable lease. Consequently, a ROU lease asset of $592,304 which reflects an $84,858 unfavorable adjustment based on the fair value of the lease terms and a corresponding lease liability of $677,163 based on the present value of the minimum rental payments of such lease was recorded at the date of ASP Isotopes acquisition of 51% of PET Labs. Dr. Gerdus Kemp, an officer of PET Labs and an employee of ASP UK, is the sole owner of the facility under this lease agreement.

A summary of long-term leases in the condensed consolidated balance sheet as of June 30, 2025 is as follows:


	ROU Asset		Operating Lease Liability - Current		Operating Lease Liability – Non-Current		Total Operating Lease Liability
Office and laboratory, Pretoria, South Africa	$	533,972	$	74,397	$	550,479	$	624,876
Additional production, Pretoria, South Africa		131,857		131,857		—		131,857
Laboratory, Pretoria, South Africa		36,228		27,879		10,381		38,260
Office, Pretoria, South Africa		99,457		24,287		78,559		102,846
Office and production, Pretoria, South Africa		215,046		242,453		—		242,453
Total	$	1,016,560	$	500,873	$	639,419	$	1,140,292

A summary of long-term leases in the condensed consolidated balance sheet as of December 31, 2024 is as follows:


	ROU Asset		Operating Lease Liability - Current		Operating Lease Liability – Non-Current		Total Operating Lease Liability
Office and laboratory, Pretoria, South Africa	$	538,942	$	63,703	$	554,332	$	618,035
Additional production, Pretoria, South Africa		211,829		179,948		31,881		211,829
Laboratory, Pretoria, South Africa		45,433		23,653		23,674		47,327
Office and production, Pretoria, South Africa		325,930		290,372		78,592		368,964
Total	$	1,122,134	$	557,676	$	688,479	$	1,246,155

A lease for additional production space in Pretoria, South Africa commenced prior to October 31, 2023 with the initial term expiring in March 2024 and the Company is maintaining the lease under the agreed upon monthly extensions. The Company has applied the guidance in ASC 842 and has determined that this lease is a short-term lease effective on the date of ASP Isotopes acquisition of 51% of PET Labs and expensed the monthly payments for the six months ended June 30, 2025 and 2024.

Quantitative information regarding the Company’s operating lease liabilities is as follows:


	Three Months Ended June 30,						Six Months Ended June 30,
	2025			2024			2025			2024
Operating Lease Cost
Operating lease cost	$	185,006		$	167,692		$	353,464		$	316,592
Other Information
Operating cash flows paid for amounts included in the measurement of lease liabilities	$	178,004		$	162,037		$	343,108		$	305,375
Operating lease liabilities arising from obtaining right-of- use assets	$	101,929		$	—		$	101,929		$	364,458
Weighted average remaining lease term (years)		3.56			3.80			3.56			3.80
Weighted average discount rate		9.49	%		10.12	%		9.49	%		10.12	%

Future lease payments under noncancelable operating lease liabilities as of June 30, 2025 are as follows:


	Operating Leases
Future Lease Payments
2025 (remaining six months)	$	361,681
2026		312,189
2027		178,256
2028		161,993
2029		153,042
Thereafter		164,521
Total lease payments	$	1,331,682
Less: imputed interest		(191,390	)
Total operating lease liabilities	$	1,140,292
Less current portion	$	(500,873	)
Operating lease liability - noncurrent	$	639,419

The Company records the expense from short-term leases as incurred. Lease expense from short-term leases was $64,418 and $43,205 for the six months ended June 30, 2025 and 2024, respectively, and $32,209 and $15,762 for the three months ended June 30, 2025 and 2024, respectively.

The Company accounts for finance leases in accordance with ASC 842 (Note 2). The Company is party to several ongoing finance leases in South Africa for certain fixed assets, including new finance leases for additional equipment in May and October 2024.

Quantitative information regarding the Company’s finance lease liabilities is as follows:


	Three Months Ended June 30,						Six Months Ended June 30,
	2025			2024			2025			2024
Finance Lease Cost
Interest on lease liabilities	$	23,016		$	16,893		$	45,263		$	23,933
Other Information
Operating cash flows paid for amounts included in the measurement of finance lease liabilities	$	31,920		$	24,468		$	61,831		$	38,846
Amortization of right-of-use assets	$	12,695		$	9,871		$	53,244		$	19,312
Weighted average remaining lease term (years)		4.0			4.4			4.0			4.4
Weighted average discount rate		13.1	%		12.9	%		13.1	%		12.9	%

Future lease payments under noncancelable finance lease liabilities are as follows as of June 30, 2025:


	Finance Leases
Future Lease Payments
2025 (remaining six months)	$	111,463
2026		224,690
2027		219,626
2028		180,850
2029		70,284
Thereafter		68,901
Total lease payments	$	875,814
Less: imputed interest		(211,260	)
Total lease liabilities	$	664,554
Less current portion	$	(145,976	)
Finance lease liability - noncurrent	$	518,578

The Company classifies certain of its leases as sales-type leases and records the leases within “Lease receivables” on the Company’s condensed consolidated balance sheets and records interest income in the Company’s condensed consolidated statements of operations and comprehensive loss. The Company does not have significant variable lease payments or residual value guarantees associated with these leases. Credit risk is monitored regularly, and no allowance for credit losses was recorded as of the reporting date.

In March 2025, the Company purchased a GE NM 830 Gamma Camera, a nuclear medicine machine that enables earlier disease diagnosis, patient comfort, and enhanced operational efficiency. On April 1, 2025 the Company entered into an Equipment Lease Agreement (the “Lease”) with Drs. Van Niekerk, Ramjee, Modiselle, Lengana and Louw Incorporated (“CoMIT”) for the use of certain Equipment. The term is for 120 months beginning April 1, 2025.

Future minimum lease payments to be collected under sales-type leases accounted for under ASC 842, excluding lease payments that are not fixed and determinable, as of June 30, 2025 are as follows:


	Sales-type Leases
Future Lease Payments
2025 (remaining six months)	$	26,294
2026		105,177
2027		105,177
2028		105,177
2029		105,177
Thereafter		552,177
Total undiscounted cash flows	$	999,179

Interest income recognized from sales-type leases during the three and six months ended June 30, 2025 was $22,064.