Secured and unsecured senior debt (Tables)

3 Months Ended

Mar. 31, 2025

Schedule of maturities of secured and unsecured debt

The following table summarizes our outstanding indebtedness and respective principal payments remaining as of March 31, 2025 (dollars in thousands):


	Stated Rate	Interest Rate(1)		Maturity Date(2)		Principal Payments Remaining for the Periods Ending December 31,							Unamortized (Deferred Financing Cost), (Discount)/ Premium
Debt	Stated Rate	Interest Rate(1)		Maturity Date(2)		2025	2026	2027	2028	2029	Thereafter	Principal	Unamortized (Deferred Financing Cost), (Discount)/ Premium	Total
Secured notes payable
Greater Boston(3)	SOFR+2.70%	7.20%		11/19/26		$—	$150,418	$—	$—	$—	$—	$150,418	$(199)	$150,219
San Francisco Bay Area	6.50%	6.50		7/1/36		34	36	38	41	44	395	588	—	588
Secured debt weighted-average interest rate/ subtotal		7.20				34	150,454	38	41	44	395	151,006	(199)	150,807

Unsecured senior line of credit and commercial paper program(4)	(4)	4.69	(4)	1/22/30	(4)	—	—	—	—	—	300,000	300,000	(117)	299,883
Unsecured senior notes payable	3.45%	3.62		4/30/25	(5)	600,000	—	—	—	—	—	600,000	(74)	599,926
Unsecured senior notes payable	4.30%	4.50		1/15/26		—	300,000	—	—	—	—	300,000	(408)	299,592
Unsecured senior notes payable	3.80%	3.96		4/15/26		—	350,000	—	—	—	—	350,000	(531)	349,469
Unsecured senior notes payable	3.95%	4.13		1/15/27		—	—	350,000	—	—	—	350,000	(940)	349,060
Unsecured senior notes payable	3.95%	4.07		1/15/28		—	—	—	425,000	—	—	425,000	(1,206)	423,794
Unsecured senior notes payable	4.50%	4.60		7/30/29		—	—	—	—	300,000	—	300,000	(971)	299,029
Unsecured senior notes payable	2.75%	2.87		12/15/29		—	—	—	—	400,000	—	400,000	(1,962)	398,038
Unsecured senior notes payable	4.70%	4.81		7/1/30		—	—	—	—	—	450,000	450,000	(1,964)	448,036
Unsecured senior notes payable	4.90%	5.05		12/15/30		—	—	—	—	—	700,000	700,000	(4,535)	695,465
Unsecured senior notes payable	3.375%	3.48		8/15/31		—	—	—	—	—	750,000	750,000	(4,188)	745,812
Unsecured senior notes payable	2.00%	2.12		5/18/32		—	—	—	—	—	900,000	900,000	(6,737)	893,263
Unsecured senior notes payable	1.875%	1.97		2/1/33		—	—	—	—	—	1,000,000	1,000,000	(6,892)	993,108
Unsecured senior notes payable	2.95%	3.07		3/15/34		—	—	—	—	—	800,000	800,000	(7,047)	792,953
Unsecured senior notes payable	4.75%	4.88		4/15/35		—	—	—	—	—	500,000	500,000	(4,844)	495,156
Unsecured senior notes payable	5.50%	5.66		10/1/35		—	—	—	—	—	550,000	550,000	(6,777)	543,223
Unsecured senior notes payable	5.25%	5.38		5/15/36		—	—	—	—	—	400,000	400,000	(4,024)	395,976
Unsecured senior notes payable	4.85%	4.93		4/15/49		—	—	—	—	—	300,000	300,000	(2,843)	297,157
Unsecured senior notes payable	4.00%	3.91		2/1/50		—	—	—	—	—	700,000	700,000	9,951	709,951
Unsecured senior notes payable	3.00%	3.08		5/18/51		—	—	—	—	—	850,000	850,000	(11,130)	838,870
Unsecured senior notes payable	3.55%	3.63		3/15/52		—	—	—	—	—	1,000,000	1,000,000	(13,561)	986,439
Unsecured senior notes payable	5.15%	5.26		4/15/53		—	—	—	—	—	500,000	500,000	(7,537)	492,463
Unsecured senior notes payable	5.625%	5.71		5/15/54		—	—	—	—	—	600,000	600,000	(6,636)	593,364
Unsecured debt weighted-average interest rate/subtotal		3.91				600,000	650,000	350,000	425,000	700,000	10,300,000	13,025,000	(84,973)	12,940,027
Weighted-average interest rate/total		3.95%				$600,034	$800,454	$350,038	$425,041	$700,044	$10,300,395	$13,176,006	$(85,172)	$13,090,834

(1)Represents the weighted-average interest rate as of the end of the applicable period, including amortization of loan fees, amortization of debt premiums (discounts), and other bank fees.

(2)Reflects any extension options that we control.

(3)Represents a secured construction loan held by our consolidated real estate joint venture for 99 Coolidge Avenue, of which we own a 75.7% interest. As of March 31, 2025, this joint venture has $44.9 million available under existing lender

commitments. The interest rate shall be reduced from SOFR+2.70% to SOFR+2.10% over time upon the completion of certain leasing, construction, and financial covenant milestones.

(4)Refer to “$5.0 billion unsecured senior line of credit” and “$2.5 billion commercial paper program” on the following page.

(5)Upon maturity on April 30, 2025, we expect to repay $600.0 million of our 3.45% unsecured senior notes payable.

Summary of secured and unsecured debt

The following table summarizes our secured and unsecured senior debt and amounts outstanding under our unsecured senior

line of credit and commercial paper program as of March 31, 2025 (dollars in thousands):


	Fixed-Rate Debt	Variable-Rate Debt				Weighted-Average
						Interest		Remaining Term (in years)
			Total		Percentage	Rate(1)		Remaining Term (in years)
Secured notes payable	$588	$150,219	$150,807		1.2%	7.20%		1.7
Unsecured senior notes payable	12,640,144	—	12,640,144		96.5	3.89		12.5
Unsecured senior line of credit and commercial paper program	—	299,883	299,883	(2)	2.3	4.69	(2)	4.8	(3)
Total/weighted average	$12,640,732	$450,102	$13,090,834		100.0%	3.95%		12.2	(3)
Percentage of total debt	96.6%	3.4%	100%

(1)Represents the weighted-average interest rate as of the end of the applicable period, including expense/income related to the amortization of loan fees, amortization of

debt premiums (discounts), and other bank fees.

(2)As of March 31, 2025, we had no outstanding balance on our unsecured senior line of credit and $299.9 million of commercial paper notes outstanding.

(3)We calculate the weighted-average remaining term of our commercial paper notes by using the maturity date of our unsecured senior line of credit. Using the maturity

date of our outstanding commercial paper notes, the consolidated weighted-average maturity of our debt is 12.0 years. The commercial paper notes sold during the

three months ended March 31, 2025 were issued at a weighted-average yield to maturity of 4.60% and had a weighted-average maturity term of 13 days.

Schedule of Interest Incurred

The following table summarizes interest expense for the three months ended March 31, 2025 and 2024 (in thousands):


	Three Months Ended March 31,
	2025	2024
Interest incurred	$130,941	$122,680
Capitalized interest	(80,065)	(81,840)
Interest expense	$50,876	$40,840