Key Highlights

● Micron rallied during the regular session on SK hynix's results.

● It slipped after hours in sympathy with Alphabet.

● Alphabet is among the biggest buyers of AI hardware.

● Microsoft's results offered a more positive signal.

Micron Technology shares slipped in extended trading on Wednesday, October 28, surrendering part of a strong session gain after Alphabet's earnings miss dampened enthusiasm for AI stocks.

Micron Technology (NASDAQ:MU) gave back some of its gains after the closing bell. The memory-chip maker had jumped during the regular session on the back of blockbuster results from South Korean rival SK hynix (NASDAQ:SKHY), but slid in extended trading after Alphabet's disappointing report weighed on AI-linked stocks across the Nasdaq-100.

A Strong Session

Micron was one of the day's standout performers during regular hours. SK hynix reported a more than sevenfold jump in profit, its first quarter with revenue above 100 trillion won, and said it expects the memory shortage to last into 2030. Investors took that as a signal that memory prices and demand would stay strong, and Micron, one of the three dominant makers of DRAM memory, rallied.

Other memory and storage names joined in, including Sandisk (NASDAQ:SNDK) and Seagate (NASDAQ:STX). The Philadelphia Semiconductor Index rose for a fourth straight session to close at 11,684.00, and the Nasdaq-100 rose 161.72 points to finish at 29,813.16.

The After-Hours Reversal

The mood shifted after the bell. Alphabet (NASDAQ:GOOGL) reported third-quarter earnings of $2.12 a share, far below consensus, and revenue of $127.6 billion, slightly short of estimates. Free cash flow turned negative. Alphabet slid sharply in extended trading.

Micron slipped after hours in sympathy, giving back part of the session's advance. Nvidia (NASDAQ:NVDA) also edged lower, and Nasdaq-100 futures dipped overnight. The reaction reflected Micron's close ties to AI spending: a large share of the industry's growth now comes from high-bandwidth memory, which is stacked alongside AI accelerators in data-center servers, and Alphabet is among the biggest buyers of that hardware.

Weighing the Signals

Alphabet did raise its 2026 capital spending forecast to between $195 billion and $205 billion, which signals continued heavy investment in AI infrastructure. Microsoft (NASDAQ:MSFT) also gave AI bulls a boost after the bell, rising after its Azure cloud business accelerated.

Investors are trying to square conflicting messages. SK hynix's outlook pointed to years of tight supply, while Alphabet's negative free cash flow left some investors weighing how long hyperscalers can sustain their spending pace. BCA Research's Peter Berezin offered a more cautious long-term view, saying he thinks the market is heading for an AI capex bust, though probably not until 2028.

What to Watch

The Federal Reserve left its benchmark rate range unchanged in a 10-2 vote, and long-dated Treasury yields climbed. The S&P 500 rose 21.38 points to 7,743.98, and the Nasdaq Composite added 72.04 points to 26,549.85.

The key question at Thursday's open is whether Micron's after-hours slip deepens or whether buyers return, drawn by the memory-shortage outlook from SK hynix. Amazon (NASDAQ:AMZN) reports after the close, and Apple (NASDAQ:AAPL) and Meta (NASDAQ:META) report later this week.