4. Customer Concentrations and Accounts Receivable

Accounts receivables are presented on the Condensed Consolidated Balance Sheets, net of estimated credit losses. The Company applies the aging method by pooling receivables based on levels of delinquency and applying historical loss rates on what has been historically uncollectible by aging categories. The historical loss rate is adjusted for current conditions and reasonable and supportable forecasts of future losses, as necessary. Additionally, the allowance for credit loss calculation includes subjective adjustments for qualitative risk factors that could likely cause estimated credit losses to differ from historical experience. The factors include assessments of various economic conditions, significant events that have or will occur, geographic location, size and credit ratings of the customers. The Company may also record a specific reserve for individual accounts when the Company becomes aware of specific customer circumstances, such as in

the case of a bankruptcy filing or deterioration in the customer’s operating results or financial position. Accounts deemed uncollectible are written off against the allowance for credit loss.

Changes in the current expected credit losses (“CECL”) allowance for accounts receivable are as follows (in thousands):

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Sales to Cal Microturbine and Lone Star Power Solutions, LLC (“Lone Star”), two of the Company’s domestic distributors, accounted for 47% and 10% of revenue for the three months ended June 30, 2025, respectively. Lone Star, Cal Microturbine and E-Finity Distributed Generation (“E-Finity”), three of the Company’s domestic distributors and Optimal Group Australia Pty Ltd, one of the Company’s international distributors, accounted for 16%, 13%, 11% and 11% of revenue for the three months ended June 30, 2024, respectively.

Additionally, Cal Microturbine and Lone Star accounted for 33% and 13% of accounts receivable as of June 30, 2025, respectively. Lone Star and Optimal Group Australia accounted for accounted for 18% and 10% of accounts receivable as of March 31, 2025, respectively. The Company recorded a credit loss expense of $0.2 million and $0.1 million during the three months ended June 30, 2025 and 2024, respectively.