Secured and unsecured senior debt (Tables)


	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 note payable
Greater Boston(3)	SOFR+2.70%	7.16%		11/19/26	(3)	$—	$153,624	$—	$—	$—	$—	$153,624	$(124)	$153,500

Unsecured senior line of credit and commercial paper program(4)	(4)	4.71	(4)	1/22/30	(4)	—	—	—	—	—	1,100,000	1,100,000	(2,007)	1,097,993
Unsecured senior notes payable	4.30%	4.50		1/15/26		—	300,000	—	—	—	—	300,000	(284)	299,716
Unsecured senior notes payable	3.80%	3.96		4/15/26		—	350,000	—	—	—	—	350,000	(408)	349,592
Unsecured senior notes payable	3.95%	4.13		1/15/27		—	—	350,000	—	—	—	350,000	(812)	349,188
Unsecured senior notes payable	3.95%	4.07		1/15/28		—	—	—	425,000	—	—	425,000	(1,100)	423,900
Unsecured senior notes payable	4.50%	4.60		7/30/29		—	—	—	—	300,000	—	300,000	(916)	299,084
Unsecured senior notes payable	2.75%	2.87		12/15/29		—	—	—	—	400,000	—	400,000	(1,860)	398,140
Unsecured senior notes payable	4.70%	4.81		7/1/30		—	—	—	—	—	450,000	450,000	(1,872)	448,128
Unsecured senior notes payable	4.90%	5.05		12/15/30		—	—	—	—	—	700,000	700,000	(4,339)	695,661
Unsecured senior notes payable	3.375%	3.48		8/15/31		—	—	—	—	—	750,000	750,000	(4,027)	745,973
Unsecured senior notes payable	2.00%	2.12		5/18/32		—	—	—	—	—	900,000	900,000	(6,506)	893,494
Unsecured senior notes payable	1.875%	1.97		2/1/33		—	—	—	—	—	1,000,000	1,000,000	(6,675)	993,325
Unsecured senior notes payable	2.95%	3.07		3/15/34		—	—	—	—	—	800,000	800,000	(6,857)	793,143
Unsecured senior notes payable	4.75%	4.88		4/15/35		—	—	—	—	—	500,000	500,000	(4,730)	495,270
Unsecured senior notes payable	5.50%	5.66		10/1/35		—	—	—	—	—	550,000	550,000	(6,624)	543,376
Unsecured senior notes payable	5.25%	5.38		5/15/36		—	—	—	—	—	400,000	400,000	(3,939)	396,061
Unsecured senior notes payable	4.85%	4.93		4/15/49		—	—	—	—	—	300,000	300,000	(2,814)	297,186
Unsecured senior notes payable	4.00%	3.91		2/1/50		—	—	—	—	—	700,000	700,000	9,916	709,916
Unsecured senior notes payable	3.00%	3.08		5/18/51		—	—	—	—	—	850,000	850,000	(11,034)	838,966
Unsecured senior notes payable	3.55%	3.63		3/15/52		—	—	—	—	—	1,000,000	1,000,000	(13,450)	986,550
Unsecured senior notes payable	5.15%	5.26		4/15/53		—	—	—	—	—	500,000	500,000	(7,482)	492,518
Unsecured senior notes payable	5.625%	5.71		5/15/54		—	—	—	—	—	600,000	600,000	(6,580)	593,420
Unsecured debt weighted-average interest rate/subtotal		3.97				—	650,000	350,000	425,000	700,000	11,100,000	13,225,000	(84,400)	13,140,600
Weighted-average interest rate/total		4.01%				$—	$803,624	$350,000	$425,000	$700,000	$11,100,000	$13,378,624	$(84,524)	$13,294,100

(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, where we have a 76.9% interest. As of June 30, 2025, this joint venture has $41.7 million available under existing lender

commitments. We expect to repay the entire $153.5 million balance in August 2025.

line of credit and commercial paper program as of June 30, 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 note payable	$—	$153,500	$153,500		1.2%	7.16%		1.4
Unsecured senior notes payable	12,042,607	—	12,042,607		90.5	3.90		12.8
Unsecured senior line of credit and commercial paper program	—	1,097,993	1,097,993	(2)	8.3	4.71	(2)	4.6	(3)
Total/weighted average	$12,042,607	$1,251,493	$13,294,100		100.0%	4.01%		12.0	(3)
Percentage of total debt	90.6%	9.4%	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 June 30, 2025, we had no outstanding balance on our unsecured senior line of credit and $1.1 billion 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 11.6 years. The commercial paper notes sold during the six

months ended June 30, 2025 were issued at a weighted-average yield to maturity of 4.67% and had a weighted-average maturity term of 16 days.


	Three Months Ended June 30,		Six Months Ended June 30,
	2025	2024	2025	2024
Interest incurred	$137,719	$126,828	$268,660	$249,508
Capitalized interest	(82,423)	(81,039)	(162,488)	(162,879)
Interest expense	$55,296	$45,789	$106,172	$86,629