Nvidia is 13% of SK hynix sales. So is somebody else.

SK hynix's semiannual report, filed on the 14th, discloses 17.6087 trillion won ($12.7 billion) of first-half sales to a single external customer, or 13.35% of the total, down from the 24% of annual sales the company booked from Nvidia last year ^[1][4]. The number that matters more is the one directly beneath it: a second unnamed single external customer at 17.1874 trillion won ^[3].

Seoul Economic Daily reports the first customer is understood to be Nvidia, SK hynix's largest client, and presumes the second is a large data center memory buyer such as Microsoft or Google ^[2][3]. Neither is named in the filing, so the identification is inference, not disclosure ^[1][3]. What the filing does establish is the size of the gap: 421.3 billion won, which makes customer two equal to 97.6% of customer one ^[3]. Two buyers, functionally the same size, together 26.4% of group revenue ^[4].

The disclosures triangulate. Backing out from the 13.35% share gives first-half sales of roughly 131.9 trillion won; the US figure of 84.5648 trillion won at 64.1% and the China figure of 32.4783 trillion won at 24.6% both land on the same total ^[1][8][9][1]. Customer two therefore sits at about 13.03% of sales ^[2]. The US and China together account for 88.7% of the half ^[5], with US shipments weighted to AI server product and China to mobile parts such as low-power DRAM and NAND ^[10].

Read the 24% to 13.35% move carefully. It is a share comparison across different periods, and the source does not give last year's revenue base, so it does not establish that Nvidia bought less in absolute terms ^[1][4]. On share alone the decline is 10.65 percentage points ^[6]. The more defensible reading is dilution: SK hynix says it has diversified toward big tech firms building their own ASICs as an alternative to GPUs ^[5], and the filing shows that a customer outside the GPU channel can now write cheques the same size as Nvidia's ^[1][3][3].

The concentration picture is also less alarming than a single 13% line suggests. If both top customers are US-based, they account for about 41% of American revenue, leaving the majority of the largest region spread across buyers too small to trip disclosure ^[8][7].

Direction of travel for the second half runs the other way. Seoul Economic Daily reports Nvidia's share is expected to expand somewhat as SK hynix concentrates HBM4 supply around the Vera Rubin launch ^[6]. On the second-quarter call, the company said it began mass-production HBM4 supply to major customers in the second quarter, completed HBM4E sample supply, and is in talks with major customers on 2027 HBM volumes and prices ^[7].

Watch the next filing for whether the two top customers stay within a few hundred billion won of each other or Nvidia pulls away on HBM4 allocation ^[1][3][6]. Watch the 2027 pricing talks, because a supplier negotiating with two buyers of equal weight has a different hand than one negotiating with a single anchor ^[7][3]. And watch whether a third customer crosses the disclosure threshold.