One unnamed customer is 56.8% of Alpha & Omega Semiconductor's revenue and 70.3% of its receivables

Alpha & Omega Semiconductor·−3.05% — Alpha & Omega Semiconductor, down 3.05 percent as of its last quote, a power-chip supplier to servers, PCs and smartphones, filed its quarterly report on November 6↗, a day after its earnings release↗ ¹⁵. One line in the filing is the fact the release left out: a buyer identified only as Customer B took 56.8% of September-quarter revenue ¹. None of the earnings coverage picked it up either ²³⁴⁷.

The growth is price, moving through a narrow channel

The chain from datacenter to filing runs through power delivery. AI servers need denser voltage conversion, and AOSL's medium-voltage MOSFETs, the transistor switches inside the intermediate bus converters that step down power in a server, are what that build-out buys ⁶. AI and server revenue grew 250% year over year to about a fifth of company revenue, from 5.5% a year earlier ⁵⁶.

The mix shows the shape: discrete transistor revenue rose by more than a quarter while power-management chip revenue fell by nearly half, and unit shipments fell almost a fifth while average selling prices rose by a fifth ¹. Nearly all of the quarter's revenue shipped through Hong Kong, where AOSL sells primarily through distributors ¹. Fewer, larger, higher-priced orders through a narrow channel is the pattern that ends with one buyer taking half the quarter.

The dependence deepened as the story improved

Customer B was already more than half of revenue a year ago, and its share of receivables has climbed again since June ¹. Customer A, the next-largest buyer, slipped to 15.3% of revenue from 21.8% ¹. On the earnings call↗, chief executive Stephen Chang described an AI business spreading across power-supply makers and module makers, "a little more diversification than simply just going after one big opportunity" ⁶.

The customer table moves the other way. The net loss widened year over year even as gross margin improved ¹, and December guidance of $170–190 million↗, growth in a usually softer quarter, likely holds only if the big buyer keeps ordering ³⁶⁷.

A pause by Customer B would hit sales and collections together

Most of the receivables sit in one hand, so a pause would cut revenue and cash collection at once, and the loss would widen again ¹. No public source names the buyer, and nothing filed shows whether it is stocking up or working inventory down.

The market values AOSL near $704 million on the AI story ⁴. That number rests on Customer B repeating its orders; it breaks if the buyer digests inventory or shifts suppliers, and it strengthens when a second large name shows up.

Next filing, read the customer table first. Until a second name appears beside Customer B, the AI turnaround and one buyer's order book are the same bet.