Key Highlights

  • Micron reported fiscal third-quarter Revenue of $41.46bn and GAAP Net Income of $28.24bn, guiding to roughly $50.0bn of revenue and an 86% gross Margin for the fourth quarter.
  • Sandisk's fiscal fourth-quarter revenue reached $8.97bn, up 51% sequentially, with full-year revenue of $20.25bn, up 175%, and a gross margin of 84.6%.
  • Western Digital's fiscal fourth-quarter revenue rose 44% year on year to $3.75bn, with full-year revenue of $12.92bn as AI data centres effectively sold out its hard-drive output for the year.

The artificial-intelligence story is usually told through the graphics processors that do the heavy computing, but those chips are useless without somewhere to keep data and a fast way to feed it in. That is why memory and storage have moved from the background of the S&P 500's AI narrative to its centre. Three US-listed constituents, Micron Technology (NASDAQ:MU), Sandisk (NASDAQ:SNDK) and Western Digital (NASDAQ:WDC), illustrate the shift, and each has just reported figures that would have looked implausible a year ago.

Micron Technology (NASDAQ:MU): Memory in the AI Era

Micron, the Idaho-based maker of DRAM and NAND flash memory listed on the Nasdaq, reported record results for its fiscal third quarter, which ended on 28 May 2026. Revenue reached $41.46bn and GAAP net income was $28.24bn, or $24.67 per diluted share. The company guided to roughly $50.0bn of revenue and a gross margin near 86% for the fourth quarter, an unusually high figure for a historically cyclical business. It also guided to fourth-quarter GAAP Earnings of about $30.73 per share.

Chief executive Sanjay Mehrotra tied the performance directly to the strategic value of memory in the AI era. Micron said its high-bandwidth memory product, HBM4, was in high-volume production for a lead customer, with the next-generation HBM4E targeted for Volume output in 2027.

Sandisk (NASDAQ:SNDK) and Western Digital (NASDAQ:WDC): Two Halves of a Split

Sandisk and Western Digital were, until early 2025, a single company. Western Digital completed the spin-off of its NAND flash Business as Sandisk in February 2025; Sandisk then joined the S&P 500 in late November 2025, replacing Advertising group Interpublic. Both now trade on the Nasdaq. Sandisk supplies flash memory and solid-state drives, while Western Digital is now essentially a hard-disk-drive specialist.

The AI supercycle has been kinder to Sandisk than almost any other index member. For the fiscal fourth quarter ended 3 July 2026 it reported revenue of $8.97bn, up 51% sequentially, with GAAP net income of $6.90bn and a gross margin of 84.6%. Full-year revenue was $20.25bn, up 175%. Management said its data-centre segment, which reached $5.15bn for the year, had become a key growth pillar; chief executive David Goeckeler pointed to ten new business-model agreements with large customers. For the first quarter of fiscal 2027 it guided to revenue of $10.3bn to $10.8bn. The shares have been among the strongest performers in the entire index during 2026, though such gains raise the stakes if flash pricing turns.

Western Digital's recovery has been quieter but substantial. For the quarter ended 3 July 2026 it reported revenue of $3.75bn, up 44% year on year, and a GAAP gross margin above 54%. Full-year revenue was $12.92bn. Management, led by chief executive Irving Tan, guided first-quarter fiscal 2027 revenue to about $4.1bn. The company has said AI data centres, which need vast quantities of cheap nearline capacity to store Training data, have effectively sold out its hard-drive output for the year, a striking turnaround for a technology many observers had written off.

A Shared Cycle, a Shared Risk

The common thread is that generative AI consumes memory and storage at every layer, from the high-bandwidth memory sitting beside a GPU to the cheap drives holding raw data. The risk is equally shared: both markets remain deeply cyclical, and today's extraordinary prices and margins reflect tight Supply that fresh capacity could erode.

Readers should monitor pricing trends for DRAM and NAND, the pace of competition in high-bandwidth memory, the level of Capital spending by the three companies, and whether their guidance for late 2026 and 2027 holds as new supply arrives. The figures above are reported results and management forecasts; confident guidance is not the same as a guarantee, and memory has punished over-optimism before.