XML 57 R40.htm IDEA: XBRL DOCUMENT v3.25.4

Pension and Post-Employment Benefits (Tables)

12 Months Ended

Dec. 31, 2025

Plan Net Pension Credit

(in millions)		2025				2024				2023
Service cost/(credit)		$	1.5			$	(4.9	)		$	3.4
Interest cost on PBO			—				18.6				19.6
Expected return on plan assets			—				(25.9	)			(25.2	)
Amortization of prior service cost			—				16.8				0.5
Amortization of actuarial net losses			—				—				(1.6	)
Recycling of residual reserves			—				138.8				—
Net periodic cost/(benefit)		$	1.5			$	143.4			$	(3.3	)

The income statement captions are shown here:

Selling, general and administrative		2025				2024				2023
Service cost/(credit)		$	1.5			$	(4.9	)		$	3.4
Other expense/(income), net		2025				2024				2023
Interest cost on PBO		$	—				18.6				19.6
Expected return on plan assets			—				(25.9	)			(25.2	)
Amortization of prior service cost			—				—				0.5
Amortization of actuarial net losses			—				—				(1.6	)
		$	—			$	(7.3	)		$	(6.7	)
Pension scheme settlement charge		2025				2024				2023
Amortization of prior service cost		$	—				16.8				—
Recycling of residual reserves			—				138.8				—
			—				155.6				—
Tax relating to the amortization of prior service cost			—				(4.2	)			—
Tax relating to the recycling of residual reserves			—				(34.7	)			—
		$	—			$	116.7			$	—

The other financial statement captions relating to the buy-out settlement are shown here:

Recognized in Other Comprehensive Income		2025				2024				2023
Recycling of residual reserves		$	—				138.8				—
Release of historic cumulative translation adjustments			—				(0.7	)			—
			—				138.1				—
Tax relating to the recycling of residual reserves			—				(34.7	)			—
Tax relating to historic cumulative translation adjustments			—				(11.0	)			—
		$	—			$	92.4			$	—
Recognized in Reclassifications out of Accumulated Other Comprehensive Loss		2025				2024				2023
Recycling of residual reserves		$	—				138.8				—
Release of historic cumulative translation adjustments			—				(0.7	)			—
			—				138.1				—
Tax relating to the recycling of residual reserves			—				(34.7	)			—
Tax relating to historic cumulative translation adjustments			—				(11.0	)			—
		$	—			$	92.4			$	—

Plan assumptions at December 31, (%):		2025		2024				2023
Discount rate		n/a			5.18				4.59
Inflation rate		n/a			2.85				2.70
Rate of return on plan assets – overall on bid-value		n/a			4.20				4.25

Plan asset allocation by category (%):		2025		2024				2023
Debt securities and insurance contracts		n/a			—				96
Cash		n/a			100				4
		n/a			100				100

Movements in PBO and Fair Value of Plan Assets

Movements in PBO and fair value of UK Plan assets are as follows:

(in millions)		2025				2024
Change in PBO:
Opening balance		$	0.1			$	424.1
Interest cost			—				18.6
Service cost/(credit)			1.5				(4.9	)
Benefits paid			—				(32.9	)
Plan amendments			—				8.4
Scheme closure expenses			(1.6	)			—
Actuarial losses/(gains)			—				3.7
Settlements			—				(419.2	)
Exchange effect			—				2.3
Closing balance		$	—			$	0.1
Fair value of plan assets:
Opening balance		$	2.5			$	459.2
Return of funds to cover historic expenses			(0.9	)			(8.4	)
Scheme closure expenses			(1.6	)			—
Benefits paid			—				(32.9	)
Actual return on assets			—				1.5
Settlements			—				(419.2	)
Exchange effect			—				2.3
Closing balance		$	—			$	2.5
Net pension asset		$	—			$	2.4

Fair Value of Pension Assets

The fair values of pension assets by level of input were as follows:

(in millions)		Quoted Prices in Active Markets for Identical Assets (Level 1)				Significant Other Observable Inputs (Level 2)				Significant Unobservable Inputs (Level 3)				Total
At December 31, 2024
Cash			2.5												2.5
Total plan assets		$	2.5			$	—			$	—			$	2.5

Reconciliation of Fair Value of Plan Assets Measured Using Significant Unobservable Inputs

The reconciliation of the fair value of the UK Plan assets measured using significant unobservable inputs was as follows:

(in millions)		Other Assets
Balance at December 31, 2023		$	438.7
Realized/unrealized gains/(losses):
Relating to assets still held at the reporting date			(2.2	)
Purchases, issuances and settlements			(438.8	)
Exchange effect			2.3
Balance at December 31, 2024		$	—

German Plan [Member]

Plan Net Pension Credit

The service cost shown in the table below has been recognized in selling, general and administrative expenses within Corporate costs and the other items recognized within other income, net.

(in millions)		2025				2024				2023
Service cost		$	—			$	—			$	0.1
Interest cost on PBO			0.3				0.3				0.3
Amortization of actuarial net loss/(gain)			—				(0.2	)			(0.5	)
Net periodic cost/(benefit)		$	0.3			$	0.1			$	(0.1	)

Plan assumptions at December 31, (%):

Discount rate			3.80				3.20				3.70
Inflation rate			2.25				2.25				2.25
Rate of increase in compensation levels			2.75				2.75				2.75

Movements in PBO and Fair Value of Plan Assets

Movements in PBO of the German plan are as follows:

(in millions)		2025				2024
Change in PBO:
Opening balance		$	9.0			$	9.1
Service cost			—				—
Interest cost			0.3				0.3
Benefits paid			(0.5	)			(0.4	)
Actuarial losses/(gains)			(0.6	)			0.5
Exchange effect			1.2				(0.5	)
Closing balance		$	9.4			$	9.0

X

- Definition

Defined Benefit Pension Plan Projected Benefit Obligation In Excess Of Fair Value Of Plan Assets [Table Text Block]

+ References

No definition available.

+ Details

Name:	iosp_DefinedBenefitPensionPlanProjectedBenefitObligationInExcessOfFairValueOfPlanAssetsTableTextBlock
Namespace Prefix:	iosp_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (d)(5)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (a)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_RetirementPlanNameAxis=iosp_GermanPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: