⚠ Replacement Economics Cut Both WaysModerate threat

The stack-replacement aftermarket looks like razor-and-blades, but the blades can cost more than they earn, and that asymmetry is a real risk. Under Bloom's long-term service agreements, the company is typically obligated to keep the systems performing, which means supplying replacement stacks as they degrade — often at Bloom's own cost. So whether the aftermarket is a profitable blade business or a loss-making warranty obligation turns entirely on the stacks' durability and replacement cost: if they last long and are cheap to make, the aftermarket is a high-margin annuity; if they degrade faster or cost more than the contracts assumed, Bloom loses money servicing its own installed base, exactly as it has at times in the past.

This risk scales with the fleet, and Bloom is now expanding its fleet at unprecedented speed. A durability or cost problem in the current generation of stacks would not be an isolated issue but a fleet-wide one, showing up as elevated service costs and charges across a rapidly-growing base of contracts — striking hardest at the part of the business that is supposed to be its most reliable. Bloom's stack technology has improved and its newer systems are designed for greater durability, and if the stacks perform as intended the aftermarket genuinely reinforces the moat. But an investor should recognize the double edge: the same replacement cycle that creates recurring demand also creates recurring cost obligations, the profitability of the aftermarket is contingent rather than guaranteed, and a reliability shortfall across a fast-scaled fleet would turn Bloom's sturdiest moat mechanism into a source of losses — which is why even the aftermarket supports a thin moat whose quality depends on execution, not a wide one that collects margin automatically — automatic collection is not the record of a firm that lost $88M in fiscal 2025¹.