The following table analyzes goodwill movement for 2023 and 2022.


(in millions)	Performance Chemicals			Fuel Specialties			Oilfield Services		Total
At December 31, 2021
Gross cost	$	111.9		$	207.6		$	44.8	$	364.3
Accumulated impairment losses		—			—			—		—
Net book amount	$	111.9		$	207.6		$	44.8	$	364.3
Exchange effect		(5.4	)		(0.1	)		—		(5.5	)
At December 31, 2022
Gross cost	$	106.5		$	207.5		$	44.8	$	358.8
Accumulated impairment losses		—			—			—		—
Net book amount	$	106.5		$	207.5		$	44.8	$	358.8
Additions		37.4			—			—		37.4
Exchange effect		3.0			0.1			—		3.1
At December 31, 2023
Gross cost	$	146.9		$	207.6		$	44.8	$	399.3
Accumulated impairment losses		—			—			—		—
Net book amount	$	146.9		$	207.6		$	44.8	$	399.3

The Company’s reporting units, the level at which goodwill is tested for impairment, are consistent with the reportable segments: Performance Chemicals, Fuel Specialties and Oilfield Services.

On December 8, 2023, the Company acquired QGP. This resulted in additional goodwill of $37.4 million recognized within our Performance Chemicals segment. See Note 5 of the Notes to the Consolidated Financial Statements for further details.

The components in each segment (including products, markets and competitors) have similar economic characteristics and the segments, therefore, reflect the lowest level at which operations and cash flows can be clearly distinguished, operationally and for financial reporting purposes, from the rest of the Company.

The Company assesses goodwill for impairment on at least an annual basis, initially based on a qualitative assessment to determine whether it is more likely than not that the fair value of a segment is less than the carrying amount. If a potential impairment is identified, then an impairment test is performed.

The Company performed its annual impairment assessment in respect of goodwill as at December 31, 2023, 2022 and 2021. Our impairment assessment concluded that there had been no impairment of goodwill in respect of those reporting units.

We believe that where appropriate the assumptions used in our impairment assessments are reasonable, but that they are judgmental, and variations in any of the assumptions may result in materially different calculations of any potential impairment charges.