Accounts payable, accrued expenses, and other liabilities (Notes)

12 Months Ended

Dec. 31, 2024

Accounts payable, accrued expenses, and tenant security deposits

The following table summarizes the components of accounts payable, accrued expenses, and other liabilities as of December

31, 2024 and 2023 (in thousands):


	December 31,
	2024		2023
Accounts payable and accrued expenses	$534,803		$524,439
Accrued construction	500,890		606,333
Acquired below-market leases	180,407		322,040
Conditional asset retirement obligations	53,968		53,083
Deferred rent liabilities	11,461		15,183
Operating lease liability	507,127	(1)	382,883
Unearned rent and tenant security deposits	691,873		548,529
Other liabilities	173,822		158,453
Total	$2,654,351		$2,610,943

(1)Balance as of December 31, 2024 includes a $135.0 million ground lease liability related to an amendment executed in July 2024 to our existing ground lease

agreement at the Alexandria Technology Square® Megacampus. For additional information, refer to “Leases in which we are the lessee” in Note 5 – “Leases” to our

consolidated financial statements.

As of December 31, 2024 and 2023, our conditional asset retirement obligations liability primarily consisted of the soil and

groundwater remediation liabilities associated with certain of our properties. Some of our properties may contain asbestos or may be

subjected to other hazardous or toxic substances, which, under certain conditions, requires remediation. We engage independent

environmental consultants to conduct Phase I or similar environmental assessments at our properties. This type of assessment

generally includes a site inspection, interviews, and a public records review; asbestos, lead-based paint, and mold surveys; subsurface

sampling; and other testing. We recognize a liability for the fair value of a conditional asset retirement obligation (including asbestos)

when the fair value of the liability can be reasonably estimated. In addition, environmental laws and regulations subject our tenants, and

potentially us, to liability that may result from our tenants’ routine handling of hazardous substances and wastes as part of their

operations at our properties. These assessments and investigations of our properties have not to date revealed any additional

environmental liability we believe would have a material adverse effect on our business and financial statements or that would require

additional disclosures or recognition in our consolidated financial statements.