The Company sponsors a defined benefit plan (the “Kirby Pension Plan”) for its inland vessel personnel and shore based tankermen. The plan benefits are based on an employee’s years of service and compensation. The plan assets consist primarily of equity and fixed income securities.

On April 12, 2017, the Company amended the Kirby Pension Plan to cease all benefit accruals for periods after May 31, 2017 for certain participants. Participants grandfathered and not impacted were those, as of the close of business on May 31, 2017, who either (a) had completed 15 years of pension service or (b) had attained age 50 and completed 10 years of pension service. Participants non-grandfathered are eligible to receive discretionary 401(k) plan contributions.

On February 14, 2018, with the acquisition of Higman Marine, Inc. (“Higman”), the Company assumed Higman’s pension plan (the “Higman Pension Plan”) for its inland vessel personnel and office staff. On March 27, 2018, the Company amended the Higman Pension Plan to close it to all new entrants and cease all benefit accruals for periods after May 15, 2018 for all participants. The Company made contributions to the Higman Pension Plan of $1.7 million, $8.2 million and $0.9 million for the years ended December 31, 2024, 2023, and 2022, respectively.

There were no investments within Level 3 of the valuation hierarchy at December 31, 2024 and 2023. All other plan assets are invested in common collective trusts and valued using the net asset value per share practical expedient and therefore not valued within the valuation hierarchy.

The Company’s investment strategy focuses on total return on invested assets (capital appreciation plus dividend and interest income). The primary objective in the investment management of assets is to achieve long-term growth of principal while avoiding excessive risk. Risk is managed through diversification of investments within and among asset classes, as well as by investing in asset classes offering sufficient liquidity and trading history.

The Company makes various assumptions when determining defined benefit plan costs including, but not limited to, the current discount rate and the expected long-term return on plan assets. Discount rates are determined annually and are based on a yield curve that consists of a hypothetical portfolio of high quality corporate bonds with maturities matching the projected benefit cash flows. The Company assumed that plan assets would generate a long-term rate of return of 6.75% in both 2024 and 2023. The Company developed its expected long-term rate of return assumption by evaluating input from investment consultants comparing historical returns for various asset classes with its actual and targeted plan investments. The Company believes that its long-term asset allocation, on average, will approximate the targeted allocation.

The Company’s pension plan funding strategy is to make annual contributions in amounts equal to or greater than amounts necessary to meet minimum government funding requirements. The plan’s benefit obligations are based on a variety of demographic and economic assumptions, and the pension plan assets’ returns are subject to various risks, including market and interest rate risk, making an accurate prediction of the pension plan contribution difficult. The Company’s pension plan funding was 132% of the pension plans’ accumulated benefit obligation at December 31, 2024, including both the Kirby Pension Plan and the Higman Pension Plan.

The Company sponsors an unfunded defined benefit health care plan that provides limited postretirement medical benefits to employees who met minimum age and service requirements, and to eligible dependents. The plan limits cost increases in the Company’s contribution to 4% per year. The plan is contributory, with retiree contributions adjusted annually. The plan eliminated coverage for future retirees as of December 31, 2011. The Company also has an unfunded defined benefit supplemental executive retirement plan (“SERP”) that was assumed in an acquisition in 1999. That plan ceased to accrue additional benefits effective January 1, 2000.

The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):


	Pension Benefits												Other Postretirement Benefits
	Pension Plans						SERP						Postretirement Welfare Plan
	2024			2023			2024			2023			2024			2023
Change in benefit obligation
Benefit obligation at beginning of year	$	342,749		$	339,509		$	814		$	833		$	415		$	432
Service cost		3,395			3,695			—			—			—			—
Interest cost		17,179			18,356			39			43			20			22
Actuarial (gain) loss		(26,541	)		13,241			(33	)		91			(3	)		65
Gross benefits paid		(15,572	)		(32,052	)		(68	)		(153	)		(36	)		(104	)
Benefit obligation at end of year	$	321,210		$	342,749		$	752		$	814		$	396		$	415

Accumulated benefit obligation at end of year	$	310,714		$	326,987		$	752		$	814		$	396		$	415

Weighted-average assumption used to determine benefit obligation at end of year
Discount rate (a)		5.7	%	5.1%/5.2%				5.7	%		5.1	%		5.7	%		5.1	%
Rate of compensation increase	Service-based table			Service-based table				—			—			—			—
Health care cost trend rate
Initial rate		—			—			—			—			6.75	%		6.25	%
Ultimate rate		—			—			—			—			5.0	%		5.0	%
Years to ultimate		—			—			—			—		2032			2029

Change in plan assets
Fair value of plan assets at beginning of year	$	375,917		$	341,061		$	—		$	—		$	—		$	—
Actual return on plan assets		49,450			58,734			—			—			—			—
Employer contribution		1,654			8,174			68			153			36			104
Gross benefits paid		(15,572	)		(32,052	)		(68	)		(153	)		(36	)		(104	)
Fair value of plan assets at end of year	$	411,449		$	375,917		$	—		$	—		$	—		$	—

(a)

The 2024 discount rate was 5.7% for both the Kirby Pension Plan and the Higman Pension Plan. The 2023 discount rate was 5.1% for the Kirby Pension Plan and 5.2% for the Higman Pension Plan.

During the years ending December 31, 2024 and 2023, actual returns on plan assets performed better than expected which improved the funding positions.

The following table presents the funded status and amounts recognized in the Company’s consolidated balance sheet for the Company’s defined benefit plans and postretirement benefit plan (in thousands):


	Pension Benefits												Other Postretirement Benefits
	Pension Plans						SERP						Postretirement Welfare Plan
	2024			2023			2024			2023			2024			2023
Funded status at end of year
Fair value of plan assets	$	411,449		$	375,917		$	—		$	—		$	—		$	—
Benefit obligations		(321,210	)		(342,749	)		(752	)		(814	)		(396	)		(415	)
Funded status and amount recognized at end of year	$	90,239		$	33,168		$	(752	)	$	(814	)	$	(396	)	$	(415	)

Amounts recognized in the consolidated balance sheets
Noncurrent asset		93,023			42,698			—			—			—			—
Current liability		—			—			(105	)		(106	)		(47	)		(46	)
Long-term liability		(2,784	)		(9,530	)		(647	)		(708	)		(349	)		(369	)

Amounts recognized in accumulated other comprehensive income
Net actuarial (gain) loss	$	(96,817	)	$	(48,033	)	$	327		$	391		$	(1,613	)	$	(1,890	)
Prior service cost (credit)		—			—			—			—			—			—
Accumulated other compensation income	$	(96,817	)	$	(48,033	)	$	327		$	391		$	(1,613	)	$	(1,890	)

The following table presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan (in thousands):


	Pension Benefits								Other Postretirement Benefits
	Pension Plans				SERP				Postretirement Welfare Plan
	2024		2023		2024		2023		2024		2023
Expected employer contributions
First year	$	1,480	$	1,770	$	—	$	—	$	—	$	—

Expected benefit payments (gross)
Year one	$	17,765	$	16,696	$	108	$	108	$	48	$	47
Year two		18,247		17,513		102		103		47		46
Year three		19,056		18,169		97		98		45		44
Year four		19,656		19,096		91		93		43		43
Year five		20,356		19,860		85		88		40		41
Next five years		109,082		108,717		314		337		163		167

The components of net periodic benefit cost and other changes in plan assets and benefit obligations recognized in other comprehensive income for the Company’s defined benefit plans were as follows (in thousands):


	Pension Benefits
	Pension Plans									SERP
	2024			2023			2022			2024			2023			2022
Components of net periodic benefit cost
Service cost	$	3,395		$	3,695		$	6,538		$	—		$	—		$	—
Interest cost		17,179			18,356			14,779			39			43			29
Expected return on plan assets		(24,885	)		(22,910	)		(28,399	)		—			—			—
Amortization of actuarial (gain) loss		(2,330	)		—			34			32			23			30
Net periodic benefit cost		(6,641	)		(859	)		(7,048	)		71			66			59

Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial (gain) loss		(51,114	)		(22,583	)		(58,015	)		(32	)		91			(74	)
Recognition of actuarial (gain) loss		2,330			—			(34	)		(32	)		(23	)		(30	)
Total recognized in other comprehensive income		(48,784	)		(22,583	)		(58,049	)		(64	)		68			(104	)

Total recognized in net periodic benefit cost and other comprehensive income	$	(55,425	)	$	(23,442	)	$	(65,097	)	$	7		$	134		$	(45	)

Weighted average assumptions used to determine net periodic benefit cost
Discount rate (a)	5.1%/5.2%				5.5	%	3.0% / 3.1%				5.1	%		5.5	%		3.0	%
Expected long-term rate of return on plan assets		6.75	%		6.75	%		6.75	%		—			—			—
Rate of compensation increase	Service-based table			Service-based table			Service-based table				—			—			—

(a)

The 2024 discount rate for benefit cost is 5.1% for the Kirby Pension Plan and 5.2% for the Higman Pension Plan. The 2023 discount rate for benefit cost is 5.5% for both the Kirby Pension Plan and the Higman Pension Plan.

The components of net periodic benefit cost and other changes in benefit obligations recognized in other comprehensive income for the Company’s postretirement benefit plan were as follows (in thousands):


	Other Postretirement Benefits
	Postretirement Welfare Plan
	2024			2023			2022
Components of net periodic benefit cost
Interest cost	$	20		$	22		$	17
Amortization of actuarial gain		(280	)		(344	)		(394	)
Net periodic benefit cost		(260	)		(322	)		(377	)

Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		(3	)		65			(58	)
Recognition of actuarial gain		280			344			394
Total recognized in other comprehensive income		277			409			336

Total recognized in net periodic benefit cost and other comprehensive income	$	17		$	87		$	(41	)

Weighted average assumptions used to determine net periodic benefit cost
Discount rate		5.1	%		5.5	%		3.0	%
Health care cost trend rate:
Initial rate		6.25	%		6.50	%		6.25	%
Ultimate rate		5.0	%		5.0	%		5.0	%
Years to ultimate	2029			2029			2027

The Company also contributes to a multiemployer pension plan pursuant to a collective bargaining agreement which covers certain vessel crew members of its coastal operations and expires on April 30, 2027. The Company began participation in the Seafarers Pension Trust (“SPT”) with the Penn Maritime, Inc. acquisition on December 14, 2012.

Contributions to the SPT are made currently based on a per day worked basis and charged to expense as incurred and included in costs of sales and operating expenses in the consolidated statement of earnings. During 2024 and 2023, the Company made contributions of $0.7 million and $0.4 million, respectively, to the SPT. The Company’s contributions to the SPT did not exceed 5% of total contributions to the SPT in 2023. Total contributions for 2024 are not yet available. The Company did not pay any material surcharges in 2024 and 2023.

The federal identification number of the SPT is 13-6100329 and the Certified Zone Status is Green at December 31, 2023. The Company’s future minimum contribution requirements under the SPT are unavailable because actuarial reports for the 2024 plan year are not yet complete and such contributions are subject to negotiations between the employers and the unions. The SPT was not in endangered or critical status for the 2023 plan year, the latest period for which a report is available, as the funded status was in excess of 100%. Based on the most recent communication from the SPT, there would be no withdrawal liability if the Company chose to withdraw from the SPT although the Company currently has no intention of terminating its participation in the SPT.

The Company also contributes to a multiemployer pension plan pursuant to a collective bargaining agreement which covers certain employees of KDS in New Jersey and expires on October 8, 2028. The Company began participation in the Central Pension Fund of the International Union of Operating Engineers and Participating Employers (“CPF”) with the Stewart & Stevenson LLC acquisition on September 13, 2017.

Contributions to the CPF are made currently based on a fixed hourly rate for each hour worked or paid basis (in some cases contributions are made as a percentage of gross pay) and charged to expense as incurred and included in costs of sales and operating expenses in the consolidated statement of earnings. During 2024 and 2023, the Company made contributions of $0.6 million in each year to the CPF. Total contributions for the 2024 plan year are not yet available. The Company did not pay any material surcharges in 2024 and 2023.

The federal identification number of the CPF is 36-6052390 and the Certified Zone Status is Green at January 31, 2024. The Company’s future minimum contribution requirements under the CPF are unavailable because actuarial reports for the 2024 plan year, which ended January 31, 2024, are not yet complete and such contributions are subject to negotiations between the employers and the unions. The CPF was not in endangered or critical status for the 2023 plan year, ending January 31, 2024, the latest period for which a

report is available, as the funded status was 108%. There would be no withdrawal liability if the Company chose to withdraw from the CPF although the Company currently has no intention of terminating its participation in the CPF.

In addition to the defined benefit plans, the Company sponsors various defined contribution plans for substantially all employees. The aggregate contributions to the plans were $31.6 million, $26.9 million, and $27.9 million in 2024, 2023, and 2022, respectively.