US and South Korean tech stocks move in lockstep at highest level since 2021 on AI wave

UBS now expects artificial intelligence capital expenditure to reach nearly $1 trillion in 2026 before climbing to around $1.4 trillion in 2027, with surging memory costs accounting for most of the increase. The bank's updated estimates put total AI capex at $998 billion this year, almost double the $506 billion recorded in 2025, and forecast spending of $1.447 trillion next year. Memory is emerging as the main source of that growth, with UBS estimating memory spending will climb from $71 billion in 2025 to $367 billion this year and $923 billion in 2027, while other AI-related costs are estimated at $631 billion in 2026 before declining to $525 billion next year. That means higher memory costs will account for about 60% of the increase in AI capex this year and more than the entire net increase in 2027, and across the two years UBS calculates that roughly 90% of the nearly $1 trillion increase in AI capital expenditure between 2025 and 2027 will come from higher memory spending. Memory represented about 14% of total AI capex in 2025, a share the bank estimates will rise to 37% this year and reach 64% in 2027, and UBS said price-driven increases would add relatively little to real U.S. gross domestic product, instead representing a transfer of income and profits toward memory producers in Asia.

Micron Technology and Intel CEOs cautioned that memory chip shortages and higher prices could persist through 2027, with Micron's leadership indicating on a recent call that supply constraints may only start to ease meaningfully from 2028 onward. Intel's CEO echoed the outlook for extended tightness in DRAM and NAND availability, pointing to heavy AI and data center demand. Micron Technology designs and produces memory and storage hardware used in everything from smartphones and PCs to data centers, so long running tightness in DRAM and NAND supply directly touches the products it sells into these markets. As one of the larger US based chip manufacturers by scale, with a reported market value of about $1.1 trillion, its comments on supply conditions can influence how investors think about capacity planning across the wider semiconductor sector. The clearest test of this read will be how Micron's long term customer agreements and utilization plans look through 2027, especially whether the company keeps reporting high take or pay coverage across its AI oriented memory output as new fabs and its 512GB DDR5 modules move toward volume production in the second half of 2027.

S&P 500 earnings are expected to increase by +24% from the same period last year in the third quarter, the 8th straight quarter of double-digit earnings growth for the index, according to Zacks Investment Research. Earnings are expected to be above the year-earlier level for 14 of the 16 Zacks sectors, with 5 sectors expected to enjoy double-digit growth: Aerospace up +159.3%, Energy up +111.9%, Tech up +41.9%, Basic Materials up +31.2%, and Transportation up +15.1%. The Conglomerates sector is the only one expected to have lower earnings in Q3 relative to the same period last year, down 35.4%, while Consumer Staples earnings are expected to be flat. Excluding the Energy sector, Q3 earnings growth for the S&P 500 drops to +20% from +24%, and excluding the Tech sector, growth for the rest of the index drops to +14.4%. Nvidia's Q3 earnings are expected to increase +90% year-over-year on +91.2% higher revenues, while Micron's year-over-year earnings and revenue growth rates are expected to be +938% and +348.6%, respectively, and Tech sector earnings growth gets cut by slightly more than half once contributions from Nvidia and Micron are excluded. The Q3 earnings season will get the spotlight when the big banks report on October 13th, but the reporting cycle actually got underway with the September 10th quarterly releases from Oracle and Adobe, followed by homebuilder Lennar as the third S&P 500 member to report such Q3 results, with an additional six index members on deck this week including Costco, AutoZone and Darden. Total Q3 earnings for the three S&P 500 members that have reported results already are up +22.6% from the same period last year on +14.9% higher revenues, with 33.3% beating EPS estimates and 66.7% besting revenue estimates.