Samsung will reportedly have TSMC make the base die for Nvidia's custom HBM on 3nm

Samsung Electronics will use TSMC's 3-nanometer process to make the base die for Nvidia's next custom high-bandwidth memory (HBM), the Seoul Economic Daily reported on Sunday, October 18, 2026, citing industry sources. It would be the first time Samsung has handed part of its HBM production to TSMC, its main rival in contract chipmaking. Neither company has confirmed the arrangement. Samsung shares rose 1.29% in the ten minutes after the story reached the MoveSurge news feed at 10:04:27 a.m. Seoul time on Monday, from 213,250 won to 216,000 won.

What the base die does in Nvidia's NVHBM

An HBM stack is a pile of DRAM chips, the core dies, sitting on a base die that links them to the processor. In NVHBM, Nvidia's custom version, the memory controller moves out of the GPU and into the base die, so the base die becomes a logic chip built to Nvidia's design. According to the report, Nvidia asked all three HBM makers, Samsung, SK hynix and Micron, to build NVHBM base dies on TSMC's 3nm process and to make the core dies on the sixth-generation 1c DRAM process. Different manufacturing methods at each supplier make it hard to deliver the same performance, and one shared process also cuts the work of testing each supplier's chips separately.

Samsung had kept the whole job in-house

Until now Samsung has made both the core dies and the base die itself, and has offered customers memory, foundry and packaging as one package. SK hynix took the other route in April 2024, when it signed a memorandum of understanding with TSMC to use TSMC's logic process for its HBM4 base die. In August 2026, Samsung's own 4nm foundry lines were reported fully booked through 2027, with HBM4 base dies and Nvidia orders driving the demand.

Samsung reportedly agreed to Nvidia's terms after an internal review. It plans to keep making standard HBM and custom memory for other customers in-house, and it is checking whether its own foundry could produce NVHBM base dies if Nvidia's demand exceeds what TSMC can supply. The report did not say which Nvidia products will use NVHBM, when production starts or how many chips are involved.

How the stock traded

The Korean report came out on Sunday, so the news was already public when the Seoul market opened at 9 a.m. on Monday. By the time the story reached the MoveSurge news feed, Samsung had been trading for an hour. One minute later the stock was up 0.23% at 213,750 won. Our reaction reading put it at 216,000 won, up 1.29%, ten minutes after the headline, and the one-minute bars in the chart show the same price at the eleven-minute mark. Other news may also have affected the price in that window.