SanDisk Corp’s (SNDK) Impact on Small/Mid Cap Returns

Soumya Eswaran

Mon, September 21, 2026 at 5:39 AM PDT 4 min read

Riverwater Partners, an investment management company, released its 'Sustainable Value Strategy' Q2 2026 investor letter. The letter can be downloaded here. Small-cap stocks achieved their best first-half performance since 1991, with the Russell 2500 Value Index rising 17%, driven by the technology sector. The Sustainable Value Strategy underperformed its benchmark in the second quarter. The shortfall was driven almost entirely by stock selection, particularly the absence of SanDisk (SNDK), which rose approximately 720% year to date and contributed an estimated 6% of the Russell 2500 Value Index's 2026 return. Technology became the strategy's largest overweight at 17%, largely because index reconstitution sharply reduced the benchmark's technology allocation. Looking ahead to 2026, the outlook for small-cap equities remains constructive due to improving monetary conditions and attractive valuations, despite a lack of anticipated rotation toward higher-quality businesses. The firm remains committed to disciplined, quality-focused investing; historically, quality prevails over the long term. Additionally, reviewing the Fund's top five holdings could help identify its best picks for 2026.

In its second-quarter 2026 investor letter, Riverwater Sustainable Value Strategy highlighted Sandisk Corporation (NASDAQ:SNDK). Sandisk Corporation develops, manufactures, and sells data storage devices and solutions using NAND flash technology in the United States and internationally. On September 18, 2026, Sandisk Corporation (NASDAQ:SNDK) closed at $1,791.82 per share. Over the past month, Sandisk Corporation (NASDAQ:SNDK) returned 20.01%, but its shares are up 1,640.98% over the past year. Sandisk Corporation (NASDAQ:SNDK) has a market capitalization of $262.35 billion, and its stock has traded within a 52-week range of $90.22 to $2,354.39.

Riverwater Sustainable Value Strategy stated the following regarding Sandisk Corporation (NASDAQ:SNDK) in its Q2 2026 investor letter:

"Intellectual honesty requires us to address the primary driver of Russell 2500 Value performance in 2026 that was absent from our portfolio: Sandisk Corporation (NASDAQ:SNDK). Spun off from Western Digital in February 2025, this NAND flash memory company appreciated approximately 720% year-to-date and roughly 4,000% over the trailing twelve months. At its peak, SanDisk comprised nearly 5% of the Russell 2500 Value Index and accounted for an estimated 6% of the index's year-to-date 2026 return. All driven by a single stock. The fundamental story is real. AI data centers require enormous quantities of high-performance NAND flash storage.

We did not own SanDisk. Memory semiconductors remain a cyclical commodity business. NAND pricing is dictated by supply and demand at the industry level rather than individual competitive advantages, effectively rendering producers price-takers rather than price makers. Historically, these companies have earned poor returns on invested capital across the cycle, punctuated by concentrated bursts of enormous profitability when supply is tight. SanDisk in 2026 is in the tight-supply period. SanDisk also exceeded our market capitalization threshold, starting the year above $40 billion — well outside our investable range. By the time it was reconstituted out of the Russell 2500 Value Index at the end of the quarter, its market cap had surged past $250 billion. We believe it is more important to maintain discipline regarding our mandate than to compromise our investment framework simply to avoid the discomfort of short-term underperformance."