PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS

12 Months Ended

Dec. 31, 2025

PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS [Abstract]

PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS

NOTE 15 —PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS:

Defined Benefit Pension Plan

In September 2024, the Company contributed $3.6 million into the OSG Ship Management (UK) Ltd. Retirement Benefits Plan (the “Plan”) to allow the Trustee of the Plan to purchase a $21.0 million insurance contract tailored to match the full value of future Plan benefits payable from the Plan. In this arrangement, the Company’s pension benefit obligation and related risks and rewards are not transferred to the insurance company, and as a result, the Company continues to be responsible for paying the benefits. However, this arrangement generally constitutes an economic settlement of the liability by eliminating relevant risks associated with changes to the obligation, including investment, interest rate and longevity risk. The contract is accounted for as a plan asset in the accompanying consolidated balance sheets as of December 31, 2025 and 2024. As this arrangement does not qualify for settlement accounting under ASC 715, Compensation – Retirement Benefits, the corresponding obligation is netted against the plan asset in the accompanying consolidated balance sheet.

The Company expects the benefits due to the participants under the Plan to be transferred to the insurance company after the completion of their standard review of the Plan’s underlying data in approximately twenty-four months (i.e., December 2027) with minimal or no additional cost to the Company. At such time, the Company believes the arrangement will qualify for settlement accounting.

Information with respect to the Plan for which INSW uses a December 31 measurement date, is as follows:

(Dollars in thousands)	December 31, 2025		December 31, 2024
Change in benefit obligation:
Benefit obligation at beginning of year	$	18,720	$	17,876
Interest cost on benefit obligation		812		797
Actuarial losses		598		1,233
Benefits paid		(1,356)		(890)
Foreign exchange losses/(gains)		1,365		(296)
Benefit obligation at year end		20,139		18,720
Change in plan assets:
Fair value of plan assets at beginning of year		18,679		17,703
Actual return on plan assets		1,367		(1,373)
Employer contributions		—		3,649
Benefits paid		(1,356)		(890)
Foreign exchange gains/(losses)		1,361		(410)
Fair value of plan assets at year end		20,051		18,679
Unfunded status at December 31	$	(88)	$	(41)

The unfunded benefit obligation for the pension plan included in other liabilities in the accompanying consolidated balance sheets, represents the actuarial estimate of the portion of the pension plan benefit obligation that is not covered by the insurance contract purchased by the Plan. At the completion of the insurance company’s standard review of the underlying data, an additional premium cost may be incurred to cover this benefit obligation but as discussed above, such additional cost is expected to be minimal.

Information for net periodic benefit cost for the three years ended December 31, 2025 follows:

(Dollars in thousands)		2025		2024		2023
Components of expense:
Interest cost on benefit obligation	$	812	$	797	$	827
Expected return on plan assets		(811)		(914)		(1,080)
Amortization of prior-service costs		78		76		74
Recognized net actuarial loss		955		664		506
Net periodic benefit cost	$	1,034	$	623	$	327

Unrecognized actuarial losses will continue to be amortized over a period of 13 years, which represents the term to retirement of the youngest member of the Plan, until the benefits due to the participants under the Plan are formally transferred to the insurance company.

The weighted-average assumptions used to determine benefit obligations follow:

	December 31, 2025		December 31, 2024
Discount rate		4.45%		4.27%

The selection of a single discount rate for the defined benefit plan was derived from bond yield curves, which the Company believed as of such dates to be appropriate for the plan, reflecting the length of the liabilities and the yields obtainable on investment grade bonds. The assumption for a long-term rate of return on assets was based on a weighted average of rates of return on the investment sectors in which the assets are invested.

The weighted-average assumptions used to determine net periodic benefit costs follow:

	2025	2024	2023
Discount rate	4.27%	4.55%	4.90%
Expected (long-term) return on plan assets	4.27%	4.90%	6.37%
Rate of future compensation increases	-	-	-

Expected benefit payments are as follows:

(Dollars in thousands)	Pension benefits
2026	$	1,166
2027		1,211
2028		1,242
2029		1,293
2030		1,332
Years 2031-2035		6,871
	$	13,115

The fair values of the Company’s pension plan assets at December 31, 2025, by asset category are as follows:

(Dollars in thousands)	Fair Value		Level 1		Level 3 (1)
Cash and cash equivalents	$	68	$	68	$	—
Insured assets		19,983		—		19,983
Total	$	20,051	$	68	$	19,983

(1) The insured assets as of December 31, 2025 were measured using assumptions consistent with those used to measure the Plan liability as of December 31, 2025.

Multi-Employer Plans

The Merchant Navy Officers Pension Fund (“MNOPF”) is a multi-employer defined benefit pension plan covering British crew members that served as officers on board INSW’s vessels (as well as vessels of other owners). The Trustees of the MNOPF have indicated that, under the terms of the High Court ruling in 2005, which established the liability of past employers to fund the deficit on the Post 1978 section of MNOPF, calls for further contributions may be required if additional actuarial deficits arise or if other employers liable for contributions are not able to pay their share in the future. On July 11, 2024, the Company and the Trustees of the MNOPF entered into an agreement pursuant to which the Company paid $0.1 million and the Trustees of the MNOPF agreed not to seek any future contributions from the Company.

The Merchant Navy Ratings Pension Fund (“MNRPF”) is a multi-employer defined benefit pension plan covering British crew members that served as ratings (seamen) on board INSW’s vessels (as well as vessels of other owners) more than 20 years ago. Based on a High Court ruling in 2015, the Trustees of the MNRPF levied assessments to recover the significant deficit in the plan from participating employers. Participating employers include current employers, historic employers that have made voluntary contributions, and historic employers such as INSW that have made no deficit contributions. In September 2024, the Company entered into an agreement with the Trustees of the MNRPF to release the Company from any future obligation to fund deficits in the plan in exchange for the Company’s payment of $0.8 million.

The Company also made payments totaling $0.1 million in 2024 to reimburse the Trustees of the MNOPF and MNRPF for costs incurred in connection with the agreements entered into with the Company.

Defined Contribution Plans

The Company has defined contribution plans covering all eligible shore-based employees. Contributions are limited to amounts allowable for income tax purposes and include employer matching contributions to the plans. All contributions to the plans are at the discretion of the Company or as mandated by statutory laws. The employer matching contributions to the plans during each of the years ended December 31, 2025, 2024 and 2023 were $0.8 million, $0.8 million and $0.7 million, respectively.