Shares in companies linked to AI have plunged further after disappointing results from the South Korean chipmaker SK Hynix, sending the country’s stock market tumbling for the second day in a row.Seoul’s Kospi index, which is dominated by semiconductor manufacturers, slid by as much as 12.6% at one point on Wednesday, following on from a near 11% slump the previous day, reaching its lowest level since early April.This means the market is poised for a record two-day fall, representing a remarkable drop of more than 40% from a peak reached a little over a month ago. Japan’s Nikkei also declined 1.5%.Meanwhile, the oil price continued to climb, after the US military said it had knocked down an Iranian missile barrage and worked with Saudi Arabia’s forces to strike sites in Iraq that Tehran-backed militias have recently used to launch attacks.Brent crude, the international benchmark, reached $87.14 a barrel, a rise of about 3.6%, in early trading.SK Hynix, which produces the chips essential to the expansion of AI datacentres, reported record profits for the second quarter, but this still undershot investors’ expectations.That prompted a sell-off that drove its shares down by as much as 16%. Shares in the fellow chipmaker Samsung Electronics also tumbled further, trading almost 10% lower.The two companies together account for more than half of the market capitalisation of the Kospi, which has led to them holding sway over the market this year. The companies have brought in cash from investors looking to become involved in the lucrative AI trade amid the global shortage of advanced memory chips.Analysts said disappointment over SK Hynix’s earnings highlighted investors’ concerns about how long tech companies can continue their spending spree on the technology.“SK Hynix delivered strong results, but in today’s AI market, strong is ‌no longer enough,” said Gary Tan, a portfolio manager at Allspring Global Investments in Singapore.“Investors were looking for additional catalysts, particularly around long-term agreements and shareholder returns, to support a memory sector that has become the epicentre of the AI trade.”Shares in US chip companies also fell on Wall Street on Tuesday, with Intel, Advanced Micro Devices, Sandisk, Western Digital Corp and Seagate Technology all sliding.skip past newsletter promotionafter newsletter promotionApple benefited from these falls, as investors losing confidence with AI stocks sought out a safe haven. The iPhone maker’s stock briefly rose to take it above the $5tn (£3.76tn) valuation mark, the second ever company to achieve this.Shares in Taiwan’s TSMC, the world’s largest contract chipmaker, also fell on Wednesday, taking it 3% down in Taipei.Analysts said small-time investors had led the charge on buying chipmakers’ stocks, many using borrowed money. While this pushed stocks higher in last month’s rally, it has also worsened the sell-off as many have pulled their money out.“Hopes of the market rebounding today after a 10% plunge yesterday faded, triggering panic selling and forcing most stock investors to book losses,” said Han Ji-young, an analyst at Kiwoom Securities.South Korea’s finance minister, Koo Yun-cheol, told the national assembly the government was reviewing market stabilisation measures.