Memory & Optical Stocks Up 100%+ in 2026: Why We're Not Selling (Micron, SK Hynix, SanDisk, Lumentum)

Memory and optical semiconductor stocks have been the standout trade of 2026, with holdings like Micron, SK Hynix, and SanDisk up well over 100% year-to-date on tight supply and rising pricing. In this mid-year portfolio review, we break down six months of real performance across our memory holdings (Micron, SK Hynix, SanDisk, Western Digital, Seagate, NVE Corp, GSI Technology) and optical networking positions (Lumentum, Coherent, Applied Optoelectronics, Broadcom, Viavi Networks), explain why we're maintaining our allocation despite outsized gains, and walk through the risk management conversation every investor should be having right now.

We also dig into the looming supply-side risk from CXMT's IPO in China, how the "Fab Five" equipment makers (ASML, Applied Materials, Lam Research, Tokyo Electron, KLA) and Chinese players like ACM Research fit into the memory cycle, and why Lumentum and Coherent remain our top optical picks for the second half of 2026, backed by NVIDIA's direct investment in both companies. This is a research-backed, data-driven portfolio update built for long-term fundamental semiconductor investors — not stock picking hype.

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Content is for general information and entertainment only and is not investment advice. CSI owns shares of the companies discussed.