Sandisk (NASDAQ: SNDK) officially joins the S&P 100 on Monday, September 21, marking a significant reshaping of the blue-chip index’s composition.
Dell Technologies, Palo Alto Networks, and Arista Networks also enter the index on the same date, according to S&P Dow Jones Indices, which announced the changes on September 4.
Four companies are departing to make room, including Nike (NYSE: NKE), Colgate-Palmolive, Simon Property Group, and Honeywell Aerospace.
The swap reflects a dramatic reversal of fortunes, with Sandisk shares surging more than 600% in 2026, the largest gain of any stock in the S&P 500.
Nike, by contrast, hit a 52-week low this week, and Sandisk’s market value of roughly $260 billion now stands at more than four times Nike’s approximate $54 billion valuation.
The index addition will generate some forced buying from funds tracking the S&P 100, but the pool of buyers is considerably smaller than it might appear at first glance.
Sandisk already belongs to the S&P 500, meaning the largest index funds already hold the stock, and the iShares S&P 100 fund holds roughly $20 billion compared to the $837 billion held in iShares’ core S&P 500 fund.
At an estimated weight of about half a percent of the S&P 100, the iShares fund would need to purchase approximately $100 million of Sandisk stock, a modest figure given that more than $15 billion worth of shares has changed hands on a typical trading day.
The company’s extraordinary stock performance has been driven by business results rather than index mechanics, with fiscal 2026 revenue reaching $20.25 billion, up 175% year over year, and net income hitting $11.4 billion after a $1.6 billion loss the prior year.
Data center revenue surged 437% during that fiscal year, and the fiscal fourth quarter alone generated $8.97 billion in revenue, up 372% year over year, with management attributing about two-thirds of sequential growth to higher prices rather than higher volumes.
Growth is decelerating, however, with sequential revenue gains slowing from 97% in fiscal Q3 to 51% in fiscal Q4, and management guiding fiscal Q1 2027 revenue to between $10.3 billion and $10.8 billion.
Non-GAAP gross margin reached 84.6% in fiscal Q4, and guidance for the current quarter points to a range of 83% to 85%, suggesting margins may be approaching a peak.
The stock trades around $1,800 as of this writing, following an 11% jump on Friday, representing roughly 24 times earnings, a multiple that looks reasonable but depends heavily on memory pricing holding steady.
Sandisk sits approximately 24% below its June high of $2,354.39, a reminder that the stock has already demonstrated sharp moves in both directions, and its trajectory from here will be determined by memory prices, not index membership.
