Fair Value of Financial Instruments and Concentrations of Credit Risk
Fair Value of Financial Instruments
Our financial instruments include cash and cash equivalents, receivables, payables, and debt. We believe the carrying values of these instruments approximated their fair values at December 31, 2025 and 2024. Cash equivalents primarily consist of money market accounts which are measured at fair value on a recurring basis using a market approach based on quoted prices in active markets.
Concentrations of Credit Risk
Financial instruments that potentially subject us to significant concentrations of credit risk primarily consist of cash, cash equivalents, and trade accounts receivable. At December 31, 2025, substantially all of our cash and cash equivalents reside in U.K. and U.S. financial institutions or money market funds. As part of our investment strategy, we perform periodic evaluations of the relative credit standing of these financial institutions and money market funds.
Customer Revenue Concentration
We derive a significant portion of our revenues and profitability from customers operating within the utilities sector, which include power transmission service providers as well as large regulated electrical utility providers. For 2025, 2024 and 2023, revenues from our 20 largest customers represented approximately 74%, 67% and 67%, respectively, of our consolidated revenues. For 2025, our three largest customers represented 19%, 15%, and 10%, respectively, of our revenues. For 2024, our largest customer represented 19% of our revenues. For 2023, no single customer accounted for more than 10% of our consolidated revenues.
Receivables
Receivables consisted of the following at December 31:
(In thousands)20252024
Trade receivables:
Gross trade receivables$53,146 $46,819 
Allowance for credit losses(330)(948)
Net trade receivables52,816 45,871 
Income tax receivables1,651 2,049 
Other receivables5,339 26,921 
Total receivables, net$59,806 $74,841 

Other receivables as of December 31, 2025 and December 31, 2024 included $1.3 million and $23.2 million, respectively, for amounts due from the Purchaser, including the receivables and estimated deferred consideration related to the Sale Transaction (see Note 2) as well as amounts due under the transition services agreement. Other receivables as of December 31, 2025 and December 31, 2024 also included an insurance receivable of $0.4 million and $1.7 million related to a cybersecurity event.
Changes in our allowance for credit losses were as follows:
(In thousands)202520242023
Balance at beginning of year$948 $1,223 $1,193 
Credit loss expense35 (221)285 
Write-offs, net of recoveries(653)(54)(255)
Balance at end of year$330 $948 $1,223 

About Fair Value Disclosures

Fair value disclosures classify all assets and liabilities measured at fair value into a three-level hierarchy: Level 1 (quoted market prices), Level 2 (observable inputs like yield curves), and Level 3 (unobservable inputs requiring management estimates). The proportion of Level 3 assets directly reflects how much of the balance sheet depends on internal models rather than market evidence.

Key signals: a growing Level 3 balance relative to total fair-value assets increases valuation uncertainty and earnings volatility risk. Watch for transfers between levels — assets moving from Level 2 to Level 3 often signal deteriorating market liquidity. Unrealized gains and losses on Level 3 positions flow through earnings or other comprehensive income, so large swings deserve scrutiny. For financial institutions, examine the sensitivity disclosures that show how Level 3 valuations change under alternative assumptions. Compare the fair value of debt against its carrying amount to gauge hidden leverage.