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Secured and Unsecured Debt of the Operating Partnership
 12 Months Ended
Dec. 31, 2025
Debt Instrument [Line Items]  
Secured and Unsecured Debt of the Operating Partnership Secured and Unsecured Debt of the Company
In this Note 7, the “Company” refers solely to Kilroy Realty Corporation and not to any of our subsidiaries. The Company itself does not hold any indebtedness. All of our secured and unsecured debt is held directly by the Operating Partnership or its subsidiaries.

The Company generally guarantees all of the Operating Partnership’s unsecured debt obligations, including the unsecured revolving credit facility, the unsecured term loan facility, and all of the unsecured senior notes. At December 31, 2025 and 2024, the Operating Partnership had $4.0 billion outstanding in total, including unamortized discounts and deferred financing costs, under these unsecured debt obligations.

In addition, although the remaining $0.6 billion of the Operating Partnership’s debt as of December 31, 2025 and 2024 is secured and non-recourse to the Company, the Company provides limited customary secured debt guarantees for items such as voluntary bankruptcy, fraud, misapplication of payments, and environmental liabilities.

Debt Covenants and Restrictions
One of the covenants contained within the unsecured revolving credit facility, as discussed further below in Note 8, prohibits the Company from paying dividends during an event of default in excess of an amount that results in distributions to us in an amount sufficient to permit us to pay dividends to our stockholders that we reasonably believe are necessary to (i) maintain our qualification as a REIT for federal and state income tax purposes, and (ii) avoid the payment of federal or state income or excise tax.
Kilroy Realty L.P.  
Debt Instrument [Line Items]  
Secured and Unsecured Debt of the Operating Partnership Secured and Unsecured Debt of the Operating Partnership
Secured Debt

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.

The Operating Partnership’s secured debt was collateralized by operating properties with a combined net book value of approximately $950.4 million as of December 31, 2025.

Although our secured debt is secured and non-recourse to the Company and the Operating Partnership, the Company provides limited customary secured debt guarantees for items such as voluntary bankruptcy, fraud, misapplication of payments, and environmental liabilities.

The mortgage notes payable are collateralized by deeds of trust on specific real estate assets owned by the Company, as well as by the assignment of certain rents and leases associated with those properties. These secured loans generally contain customary covenants and restrictions, including limitations on additional indebtedness and requirements to maintain the properties securing the loans.

Unsecured Debt

Issuance of $400.0 million Unsecured Senior Notes Due 2036

In January 2024, the Operating Partnership issued $400.0 million aggregate principal amount of unsecured senior notes in a registered public offering. The outstanding balance of the unsecured senior notes is included in unsecured debt, net of an initial issuance discount of $4.5 million, on our consolidated balance sheets. The unsecured senior notes, which are scheduled to mature on January 15, 2036, require semi-annual interest payments each January and July based on a stated annual interest rate of 6.250%. The Operating Partnership may redeem the notes at any time, either in whole or in part, subject to the payment of an early redemption premium with respect to redemptions prior to October 15, 2035. On or after October 15, 2035, the Operating Partnership may redeem the notes at any time, either in whole or in part, at par.

Repayment of $425.0 million Unsecured Senior Notes Due 2024

In December 2024, the Company repaid the aggregate remaining principal balance of $403.7 million of the Operating Partnership’s 3.450% $425.0 million unsecured senior notes due December 15, 2024.
Unsecured Senior Notes - Registered Public Offering and Repayment

In August 2025, the Operating Partnership issued $400.0 million aggregate principal amount of unsecured senior notes in a registered public offering. The outstanding balance of the unsecured senior notes is included in unsecured debt, net of an initial issuance discount of $4.0 million, on our consolidated balance sheets. The unsecured senior notes, which are scheduled to mature on October 15, 2035, require semi-annual interest payments each April and October based on a stated annual interest rate of 5.875%. The Operating Partnership may redeem the notes at any time, either in whole or in part, subject to the payment of an early redemption premium with respect to redemptions prior to July 15, 2035. On or after July 15, 2035, the Operating Partnership may redeem the notes at any time, either in whole or in part, at par. In September 2025, the Operating Partnership used the net proceeds from the issuance of the $400.0 million 5.875% unsecured senior notes to redeem the $400.0 million aggregate principal amount of our outstanding 4.375% unsecured senior notes due October 1, 2025.

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.

Unsecured Revolving Credit Facility and Term Loan Facility

In March 2024, the Operating Partnership amended and restated the terms of its unsecured revolving credit facility. The amendment and restatement maintained the $1.1 billion borrowing capacity and extended the maturity date of the unsecured revolving credit facility to July 31, 2028.
The following table summarizes the balance and terms of our unsecured revolving credit facility:
Unsecured Revolving Credit Facility
December 31, 2025December 31, 2024
($ 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 Operating Partnership intends to borrow under the unsecured revolving credit facility from time to time for general corporate purposes, including, to finance development and redevelopment expenditures, to fund potential acquisitions, to repay long-term debt, and to supplement cash balances in response to market conditions.

In connection with amending and restating the unsecured revolving credit facility in 2024, the Operating Partnership also amended its $520.0 million unsecured term loan facility (the “2022 Term Loan Facility”). In doing so, the Operating Partnership repaid $200.0 million and extended the maturity date on $200.0 million of the principal balance by 12 months to October 3, 2025 (the “2024 Term Loan Facility”). In September 2024, the Operating Partnership repaid the remaining $120.0 million outstanding on its 2022 Term Loan Facility. In September 2025, the Operating Partnership exercised the loan extension option on the 2024 Term Loan Facility, extending the maturity date by 12 months to October 3, 2026.

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.
Financial Covenants and Restrictions

The unsecured revolving credit facility, unsecured term loan facility, unsecured senior notes, including the private placement notes, and certain other secured debt arrangements contain covenants and restrictions requiring us to meet certain financial ratios and reporting requirements. Some of the more restrictive financial covenants include a maximum ratio of total debt to total asset value, a minimum fixed-charge coverage ratio, a maximum ratio of secured debt to total asset value, a minimum unsecured debt ratio, and a minimum unencumbered asset pool debt service coverage ratio. Noncompliance with one or more of the covenants and restrictions could result in the full principal balance of the associated debt becoming immediately due and payable. We were in compliance with all of our financial covenants as of December 31, 2025 and 2024.

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.

Capitalized Interest

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