Samsung Says Q3 HBM4 Sales Tripled QoQ; 2027 HBM Supply Fully Sold Out

The sold-out 2027 book matters less as a demand headline than as a signal that buyers are locking in capacity years ahead, which shifts leverage toward suppliers with qualified HBM4 output. Samsung's tripling off a small base says little about absolute share, so the competitive question is whether this momentum translates into position against rivals already shipping in volume. The open question is how much of the sold-out supply is contracted at firm pricing versus flexible terms, since that determines whether the backlog converts into durable margin rather than a volume story.