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.

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 March 31, 2025 is as follows:


	ROU Asset		Operating Lease Liability - Current		Operating Lease Liability – Non-Current		Total Operating Lease Liability
Lease:
Office and laboratory, Pretoria, South Africa	$	536,626	$	68,854	$	552,588	$	621,442
Additional production, Pretoria, South Africa		173,615		173,615		—		173,615
Laboratory, Pretoria, South Africa		41,059		25,679		17,340		43,019
Office and production, Pretoria, South Africa		273,275		308,725		—		308,725
Total	$	1,024,575	$	576,873	$	569,928	$	1,146,801

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
Lease:
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 three months ended March 31, 2025 and 2024.

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


	Three Months Ended March 31,
	2025			2024
Operating Lease Cost
Operating lease cost	$	168,458		$	148,900
Other Information
Operating cash flows paid for amounts included in the measurement of lease liabilities	$	165,104		$	143,338
Operating lease liabilities arising from obtaining right-of- use assets	$	—		$	364,458
Weighted average remaining lease term (years)		3.58			3.94
Weighted average discount rate		9.63	%		10.23	%

Future lease payments under noncancelable operating lease liabilities as of March 31, 2025 are as follows:


	Operating Leases
Future Lease Payments
2025 (remaining nine months)	$	504,179
2026		261,317
2027		128,476
2028		138,112
2029		148,470
Thereafter		159,606
Total lease payments	$	1,340,160
Less: imputed interest		(193,359	)
Total operating lease liabilities	$	1,146,801
Less current portion	$	(576,873	)
Operating lease liability - noncurrent	$	569,928

The Company records the expense from short-term leases as incurred. Lease expense from short-term leases was $31,595 and $27,443 for the three months ended March 31, 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 March 31,
	2025			2024
Finance Lease Cost
Interest on lease liabilities	$	22,247		$	7,040
Other Information
Operating cash flows paid for amounts included in the measurement of finance lease liabilities	$	29,911		$	14,378
Amortization of right-of-use assets	$	40,549		$	9,441
Weighted average remaining lease term (years)		4.2			3.7
Weighted average discount rate		13.0	%		11.3	%

Future lease payments under noncancelable finance lease liabilities are as follows as of March 31, 2025:


	Finance Leases
Future Lease Payments
2025 (remaining nine months)	$	161,588
2026		217,978
2027		213,065
2028		175,447
2029		68,184
Thereafter		66,841
Total lease payments	$	903,103
Less: imputed interest		(226,579	)
Total lease liabilities	$	676,524
Less current portion	$	(135,011	)
Finance lease liability - noncurrent	$	541,513