The change, announced on Sept. 4 and effective before the market opened on Monday, moves SanDisk into the 100‑company subset of the broader S&P 500, a group that represents the largest U.S. blue‑chip stocks.

SanDisk’s market capitalization of roughly $260 billion now makes it more than four times the size of Nike, the sports‑wear giant it replaces, and its shares have surged more than 600 % this year – the biggest gain of any S&P 500 component.

Although the addition triggers mandatory buying by funds that track the S&P 100, the actual demand is modest. The iShares S&P 100 fund, which holds about $20 billion, would need to purchase roughly $100 million of SanDisk stock to reach a weight of about half a percent, a sum that can be absorbed in a single day of the company’s typical $15 billion‑plus trading volume.

SanDisk’s explosive performance predates the index move. After joining the S&P 500 in November 2023, the company posted fiscal 2026 revenue of $20.25 billion – a 175 % year‑over‑year increase – driven by a 437 % jump in data‑center revenue. Net income swung to $11.4 billion from a $1.6 billion loss the prior year.

The growth has been powered largely by rising NAND flash memory prices rather than volume gains. While fiscal Q4 saw a 372 % revenue rise, management warned that sequential growth is decelerating, projecting fiscal Q1 2027 revenue of $10.3‑$10.8 billion, roughly an 18 % increase from the previous quarter.

Margins have also peaked, with non‑GAAP gross margin hitting 84.6 % in Q4 and guidance of 83‑85 % for the current quarter, suggesting limited upside from pricing alone.

Analysts note that the S&P 100 inclusion is a milestone but not a catalyst for further price appreciation. The stock trades around $1,800 per share, about 24 times earnings, a multiple justified by recent earnings but vulnerable to a slowdown in memory prices.

In sum, SanDisk’s elevation to the S&P 100 underscores its mega‑cap status, yet its future stock trajectory will hinge more on the volatile memory market than on index membership.