SK hynix's HBM4 shipments fall short of expectations in the third quarter

The shortfall followed a similar miss in the second quarter. Analysts cited a partial delay in the launch schedule of Nvidia's Rubin accelerator and performance tuning of mass-produced HBM4 that is taking longer than expected.

SK hynix is still expected to post a record third-quarter operating profit. The brokerage consensus is 76.964 trillion won, an operating margin of about 78.4%, down 5.6% from 81.5122 trillion won three months earlier. Estimates range from DS Investment Securities' 70.1 trillion won to Meritz Securities' 80.1 trillion won.

Samsung closes the HBM revenue gap

Counterpoint Research put SK hynix's share of HBM revenue at 58% in the first quarter and 50% in the second. Samsung Electronics climbed from 21% to 33% over the same period, cutting the gap from 37 percentage points to 17.

Forecasts point the same way. JPMorgan projected SK hynix's HBM share would fall from 60% in 2025 to 46% this year and 41% next year. UBS expects Samsung to overtake SK hynix on bit shipments next year, at 41% against 39%.

Why the ramp slipped

TrendForce said in a June report that SK hynix's HBM4 mass production timing was pushed to the third quarter by certification delays and interface synchronization issues, and it cut its annual HBM4 shipment forecast as capacity shifted to commodity DRAM such as DDR5 and LPDDR5.

DS Investment Securities cut its target price on SK hynix from 3.1 million won to 2.64 million won in a September report, citing the won-dollar exchange rate as the biggest factor alongside product mix and revenue recognition timing during the HBM generational transition.

A semiconductor equipment industry official told Chosun Biz that SK hynix's share of Nvidia supply is highly likely to decline starting with HBM4, based on capital expenditure and HBM4 output indicators.

What SK hynix has actually shipped

SK hynix said on its second-quarter earnings call that HBM4 mass production supply to major customers began in the second quarter, with yield and quality approaching the levels of its HBM3E product. At the Hot Chips conference, Lee Jae-sik, vice president of package engineering at SK hynix America, confirmed that 12-layer HBM4 is in mass production while the 16-layer version has entered customer qualification.

The company unveiled a 48GB, 16-layer HBM4 at CES in January, one-third more capacity than its 36GB, 12-layer part. Samsung has been shipping commercial HBM4 since February, with 12-layer parts of up to 36GB.

Counterpoint Research said most Rubin-based products will likely use 12-layer HBM4, not the eight-layer configuration it had pointed to in August. An eight-layer Rubin would have cut memory content per accelerator and freed capacity for conventional DRAM; a 12-layer Rubin keeps the squeeze on.

A September report by supply-chain tracker Silicon Analysts said SK hynix had begun volume shipments of 16-layer HBM4 for Rubin. The company has not publicly confirmed those deliveries, and at a TSMC technology conference later that month it displayed a Rubin superchip fitted with its 12-layer, 36GB HBM4 while showing the 16-layer part separately.

Packaging and wafer capacity

SK hynix confirmed at Hot Chips that its MR-MUF process will carry through to the HBM4E generation, with the switch to hybrid bonding expected to arrive with HBM5. Lee identified hybrid bonding as the technology needed for stacks beyond 16 layers, to 20 or more, because taller stacks mean thinner dies and harder trade-offs between warpage and heat dissipation.

Capacity is the other constraint. Producing one HBM4 module consumes roughly three times the wafer capacity of an equivalent amount of conventional DRAM, according to a September report from KB Securities. HBM chips must also be integrated with GPUs through advanced packaging such as TSMC's chip-on-wafer-on-substrate process, so limited packaging capacity can constrain completed accelerator supply even when memory output is sufficient.

Samsung said in January that customer demand for 16-layer HBM4 was very limited and that it saw no need to commercialize the version, since it planned to sample a 12-layer HBM4E part of equivalent capacity this year. It added that it had already secured the technology to build 16-layer packages at a mass-production-ready level.

What happens next

LS Securities kept a buy rating on SK hynix but cut its target price by 27.3%, from 3.3 million won to 2.4 million won, and lowered its 2027 HBM operating margin estimate from about 80% to around 60%. The brokerage said the cut reflected a recalibration of excess profitability rather than a slowdown in HBM demand, and called a 60% margin a level customers and suppliers can both sustain.

The fourth-quarter operating profit consensus is 87.2701 trillion won, up from the third-quarter figure. Analysts expect HBM4's contribution to SK hynix revenue to rise from the fourth quarter as DRAM shipments deferred from the third quarter are recognized.

Samsung said on its second-quarter call that third-quarter HBM4 revenue would more than triple from the previous quarter and that HBM4 would account for more than 60% of its HBM revenue in the second half.

DigiTimes Taiwan reported that SK hynix may push some of this year's planned orders for HBM4 post-processing equipment into 2027, and that investment plans for next year have not been finalized. Industry watchers quoted by ad-hoc-news said the postponed shipments point to neither quality defects nor a broad disruption of HBM4 output. SK hynix is scheduled to release detailed third-quarter figures on 27 October.