Glass Substrate for Hard Disk Drives Market is valued at USD 856 million in 2025. Applying the source page’s two published size anchors consistently produces an estimated USD 833.0 million in 2026 and a projected USD 670 million by 2034, equivalent to a -2.7% CAGR during 2026–2034. Asia Pacific is the largest market, while the industry’s commercial center is shifting away from shrinking 2.5-inch consumer drives toward 3.5-inch nearline systems used in cloud and enterprise storage.