What Clean Energy Fuels Corp. told the SEC could break it.

Clean Energy Fuels' fueling-station construction program is exposed to trade policy: the administration has imposed broad-based tariffs on imports from many countries (including China, Mexico, Canada, Japan and the EU), which are expected to significantly increase the cost of procuring the materials and equipment used to construct and develop its stations; because its expected project profit is based on assumed costs, such tariff-driven cost increases, plus skilled-subcontractor-labor shortages, could cause cost overruns and project delays.

“Such tariffs are expected to cause the cost of procuring material and equipment used in the construction and development of our stations to significantly increase.”

A material part of Clean Energy Fuels' economics comes from selling Environmental Credits whose existence and value depend on government programs: the federal Renewable Fuel Standard (RFS) — under which EPA's 2014 ruling qualified transportation RNG for the most valuable D3 (cellulosic) RINs, and of which CLNE estimates it generated 31% of all U.S. D3 RINs in 2025 — and state low-carbon-fuel-standard programs such as the California LCFS; adverse changes to the RFS (annual renewable volume obligations, RIN eligibility/audits) or LCFS credit prices would directly reduce its revenue.

“The RFS program has been a key driver of growth in the RNG industry since 2014 when the EPA ruled that RNG, when used as a transportation fuel, would qualify for D3 RINs (for cellulosic biofuels), which are generally the most valuable among the four categories of RINs.”

Clean Energy Fuels' margins are exposed to natural gas commodity prices: natural gas costs represented $190.6M, $124.0M and $143.0M of cost of sales in 2023, 2024 and 2025, and the competitiveness of its vehicle fuel depends on the diesel-to-natural-gas price spread (which it partially hedges with commodity swap contracts); adverse moves in natural gas prices or the diesel spread would compress margins and reduce demand for natural gas vehicle fuel.

“Natural gas costs represented $190.6 million, $124.0 million, and $143.0 million of our cost of sales in 2023, 2024, and 2025, respectively.”

Clean Energy Fuels has emerging single-customer concentration: no customer reached 10% of total revenue in 2023, but one (undisclosed) customer accounted for 10% or more of total revenue in each of 2024 and 2025; loss or material reduction of fueling volume from that customer would adversely affect its revenue.

“During the years ended December 31, 2024 and 2025, one customer accounted for 10% or more of the Company's total revenue.”

Clean Energy Fuels concentrates its gas procurement among a few suppliers: during 2025 three suppliers each accounted for 10% or more of the company's natural gas expense relating to CNG and LNG purchases (versus one supplier in 2023), and it has long-term, quarterly natural gas purchase contracts with take-or-pay commitments; disruption, default or pricing changes from these few suppliers, or take-or-pay obligations during a demand shortfall, could raise its costs or impair supply.

“During the years ended December 31, 2023, 2024 and 2025, one , three , and three suppliers, respectively, each accounted for 10% or more of the Company's natural gas expense relating to CNG and LNG purchases.”