Micron (MU) to double HBM production capacity, narrowing gap with SK Hynix (000660 KS) and Samsung Electronics (005930 KS)

Capacity announcements in HBM follow a well-worn memory-cycle pattern: the supplier trailing on share commits capital to close the gap with the leaders, and the market reads it two ways depending on where the cycle sits. In past episodes of this kind, the first-order reaction has been positive for the expanding name, since HBM carries materially better margins than commodity DRAM and capacity commitments signal contracted demand from AI accelerator customers rather than speculative build. The second-order read is less friendly: memory has a long history of simultaneous capacity additions across the three major suppliers turning a tight, premium-priced product into an oversupplied one, and sell-side framing tends to shift quickly from share gain to industry supply discipline once all three are expanding at once. The distinction that matters is between capacity that is pre-sold under long-term agreements with the GPU complex and capacity built on spec, since only the former is margin-accretive through the cycle. Worth watching are the qualification timelines with the dominant AI chip customer, pricing commentary from the Korean incumbents, and any sign that conventional DRAM supply is being converted to HBM, which tightens the commodity side of the book and lifts blended pricing for all three.