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Secured and Unsecured Debt of the Operating Partnership (Tables) - Kilroy Realty L.P.
 12 Months Ended
Dec. 31, 2025
Debt Instrument [Line Items]  
Schedule of Unsecured Revolving Credit and Term Loan Facility
The following table summarizes the balance and terms of our unsecured revolving credit facility:
Unsecured Revolving Credit Facility
December 31, 2025December 31, 2024
($ in thousands)
Outstanding borrowings$— $— 
Remaining borrowing capacity (1)
1,100,000 1,100,000 
Total borrowing capacity (1)
$1,100,000 $1,100,000 
Interest rate (2)
5.07 %5.69 %
Annual facility fee (3)
0.250%
Unamortized deferred financing costs (3)
$9,150 $12,692 
Maturity date (4)
July 31, 2028
____________________
(1)Remaining and total borrowing capacity are further reduced by the amount of our outstanding letters of credit which total approximately $5.2 million as of December 31, 2025 and December 31, 2024. We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $500.0 million under an accordion feature pursuant to the terms of the unsecured revolving credit facility.
(2)Our unsecured revolving credit facility interest rate was calculated using the Secured Overnight Financing Rate (“SOFR”) plus a SOFR adjustment of 0.10% (together “Adjusted SOFR”) and a margin of 1.100% based on our credit rating as of December 31, 2025 and 2024. We may be entitled to a temporary 0.01% reduction in the interest rate provided we meet certain sustainability goals with respect to the ongoing reduction of greenhouse gas emissions.
(3)Our annual facility fee is paid on a quarterly basis and is calculated based on total borrowing capacity. In addition to the facility fee, we incurred debt origination and legal costs in connection with the amendment and restatement of the unsecured revolving credit facility in 2024. These costs are included in Prepaid expenses and other assets, net on our consolidated balance sheets, and will continue to be amortized through the maturity date of our unsecured revolving credit facility.
(4)The maturity date may be extended by two six-month periods, at the Operating Partnership’s election.
The following table summarizes the balance and terms of our 2024 Term Loan Facility:

2024 Term Loan Facility
December 31, 2025December 31, 2024
($ in thousands)
Outstanding borrowings (1)
$200,000 $200,000 
Interest rate (2)
5.02 %5.70 %
Unamortized deferred financing costs (3)
$277 $1,229 
Maturity date (4)
October 3, 2026October 3, 2025
____________________
(1)We may elect to borrow, subject to bank approval and obtaining commitments for any additional borrowing capacity, up to an additional $130.0 million, under an accordion feature pursuant to the terms of the 2024 Term Loan Facility, as of December 31, 2025.
(2)Our 2024 Term Loan Facility interest rate was calculated using Adjusted SOFR plus a margin of 1.200% based on our credit rating as of December 31, 2025 and 2024.
(3)We incurred debt origination and legal costs in connection with the amendment and restatement of the 2024 Term Loan Facility in 2024, which remain to be amortized through the maturity date. Additionally, in connection with extending the maturity date in September 2025, we incurred additional costs which will continue to be amortized through the extended maturity date of the 2024 Term Loan Facility.
(4)During the year ended December 31, 2025, we exercised our option to extend the maturity date by 12 months to October 3, 2026. The maturity date may be extended by an additional 12-month period, at the Operating Partnership’s election.
Schedule of Debt Maturities
The following table summarizes the stated debt maturities and scheduled amortization payments for all outstanding debt as of December 31, 2025:

Year(in thousands)
2026$601,317 
2027249,125 
2028400,000 
2029475,000 
2030500,000 
Thereafter2,400,000 
Total aggregate principal value
$4,625,442 
Less: unamortized net discounts and deferred financing costs (1)
(35,983)
Total debt, net$4,589,459 
________________________ 
(1)     Includes $25.0 million of unamortized deferred financing costs for the unsecured term loan facility, unsecured senior notes, and secured debt, and $11.0 million of unamortized discounts for the unsecured senior notes. Excludes unamortized deferred financing costs on the unsecured revolving credit facility, which are included in Prepaid expenses and other assets, net on our consolidated balance sheets.
Schedule of Capitalized Interest and Loan Fees
The following table sets forth our gross interest expense and capitalized interest. The interest expense capitalized was recorded as a cost of development and redevelopment and increased the carrying value of undeveloped land and construction in progress currently under construction:
Year Ended December 31,
202520242023
(in thousands)
Gross interest expense$211,379 $227,748 $192,983 
Capitalized interest(85,087)(82,461)(78,767)
Interest expense$126,292 $145,287 $114,216 
Secured debt  
Debt Instrument [Line Items]  
Schedule of Debt Balance and Significant Terms
The following table sets forth the composition of our secured debt:
Annual Stated
Interest Rate (1)
GAAP
Effective Rate (1) (2)
Maturity Date

December 31, 2025December 31, 2024
Type of Debt(in thousands)
Mortgage note payable3.57%3.80%December 2026$148,815 $152,668 
Mortgage note payable
4.48%4.57%July 202776,627 79,020 
Mortgage note payable5.90%6.13%August 2034375,000 375,000 
Total secured debt (3)
$600,442 $606,688 
Unamortized deferred financing costs(7,757)(8,489)
Total secured debt, net$592,685 $598,199 
____________________
(1)All interest rates presented are fixed-rate interest rates.
(2)Represents the effective interest rate including the amortization of initial issuance discounts and deferred financing costs.
(3)The secured debt and the related properties that secure this debt are held in a special purpose entity and the properties are not available to satisfy the debts and other obligations of the Company or the Operating Partnership.
Unsecured Senior Notes  
Debt Instrument [Line Items]  
Schedule of Debt Balance and Significant Terms
The following table summarizes the balance and significant terms of the unsecured senior notes issued by the Operating Partnership and outstanding, including unamortized discounts and unamortized deferred financing costs:

Maturity DateStated
Coupon
Rate
Effective
Interest
Rate (1) (2)
December 31, 2025December 31, 2024
(in thousands)
Private Placement Notes
Unsecured Senior Notes
July 20264.300%4.389%$50,000 $50,000 
Unsecured Senior Notes
October 20264.350%4.437%200,000 200,000 
Unsecured Senior Notes
February 20273.350%3.416%175,000 175,000 
Unsecured Senior Notes
February 20293.450%3.507%75,000 75,000 
Unsecured Senior Notes
January 20314.270%4.322%350,000 350,000 
Public Notes
Unsecured Senior Notes
October 20254.375%4.444%— 400,000 
Unsecured Senior Notes
December 20284.750%4.874%400,000 400,000 
Unsecured Senior Notes
August 20294.250%4.383%400,000 400,000 
Unsecured Senior Notes
February 20303.050%3.168%500,000 500,000 
Unsecured Senior Notes
November 20322.500%2.626%425,000 425,000 
Unsecured Senior Notes
November 20332.650%2.727%450,000 450,000 
Unsecured Senior Notes
October 20355.875%6.076%400,000 — 
Unsecured Senior Notes
January 20366.250%6.412%400,000 400,000 
Total Unsecured Senior Notes
$3,825,000 $3,825,000 
Less: Unamortized Net Discounts and Deferred Financing costs(27,949)(24,205)
Total Unsecured Senior Notes, Net (3)
$3,797,051 $3,800,795 
____________________
(1)Represents the effective interest rate including the amortization of initial issuance discounts and deferred financing costs.
(2)Interest on unsecured senior notes is payable semi-annually.
(3)Includes unamortized discounts of $11.0 million and $8.4 million and unamortized deferred financing costs of $16.9 million and $15.8 million as of December 31, 2025 and December 31, 2024, respectively.