How SK Hynix just pulled off the second-largest U.S. share sale by quietly powering the AI boom | Fortune

TL;DR

• 1

  SK Hynix raised $26.5 billion in the second-largest U.S. share sale ever: It debuted on the Nasdaq after the listing, the largest ever by a foreign company, and shares rose 12.8% on day one.

• 2

  The company controls roughly 60% of the global HBM market: Its high-bandwidth memory chips are inside almost every Nvidia processor, and SK Group Chair Chey Tae-won says every customer demands more despite plans to double production in five years.

• 3

  SK Hynix co-developed the world's first HBM chip with AMD in 2013: That decade-long lead gave it a dominant position when AI companies realized they needed HBM to train large language models at speed.

• 4

  The company reported $64.1 billion in revenue in 2025 with a 44% net profit margin: That was a record, beating the previous year's record, and its market value surpassed $1 trillion, making it only the second Korean company after Samsung to hit that milestone.

• 5

  South Korea's KOSPI rose 135% in the past year, almost entirely due to SK Hynix and Samsung: The two firms make up more than half of the index's market cap, and single-stock leveraged ETFs for just those two stocks have driven retail investors into a dangerous concentration.