On March 30, 2026, the U.S. memory chip giant Micron Technology found itself at the center of a dramatic stock market tumble, shedding 10% of its value in a single trading day. This sharp drop capped off a bruising eight-session stretch following Micron’s second quarter earnings announcement, with the company’s shares cumulatively down 30%. The decline, reported by CNBC and other outlets, unfolded despite Micron posting what many called “record earnings” driven by the ongoing artificial intelligence (AI) boom.
It’s a paradox that’s left investors scratching their heads. Micron, alongside SK Hynix and Samsung Electronics, is one of the main suppliers of high-bandwidth memory (HBM) chips to AI accelerator manufacturers such as Nvidia. The company’s Q2 earnings, released on March 18, blew past Wall Street’s expectations thanks to a surge in demand for AI chips. But instead of celebrating, shareholders have been racing for the exits. What’s going on?
According to Micron CEO Sanjay Mehrotra, the problem isn’t demand—if anything, it’s the opposite. Speaking to CNBC’s “Squawk on the Street” right after the earnings call, Mehrotra explained, “Major customers are receiving only half to two-thirds of their required supply due to shortages.” In other words, AI-driven demand is outpacing Micron’s ability to deliver. That supply-demand imbalance might sound like a good problem to have, but it’s left investors wary of how quickly the company—and the broader chip sector—can scale up to meet the insatiable needs of the AI revolution.
The broader tech sector didn’t escape unscathed either. On March 30, as geopolitical tensions flared in the Middle East, tech stocks across the board took a hit. The Iran war entered its fifth week, and U.S. President Donald Trump’s threats to destroy Iranian oil facilities sent international oil prices higher, rattling global markets. Cloud computing firms CoreWeave and Navis each dropped about 8%, while memory and storage companies SanDisk and Western Digital fell 7% and 9%, respectively. The mood on Wall Street was anything but celebratory.
Yet, Micron’s year-over-year story remains remarkable. Even after the recent rout, Micron’s stock is still up 270% compared to one year ago—a testament to just how feverish the AI chip market has become. That said, the recent sell-off has pared back its year-to-date gains to a modest 2%. After a brief rebound on March 27, the downward trend resumed, leaving many to wonder when—or if—the bleeding will stop.
Amidst all this, a unique group of investors known as “서학개미” (literally, “Western learning ants”—South Korean retail investors who trade U.S. stocks) continued to demonstrate their resilience and, perhaps, contrarian streak. According to data from the Korea Securities Depository, these investors maintained a net buying position in U.S. equities between March 19 and 25, even as the Iran war dragged on and volatility spiked. Their net purchases totaled $15.043 million during the period, though this was down significantly from the previous week’s $63.771 million.
During that week, the S&P 500 index slipped by 0.5% and the Nasdaq by 1.0%, only to see much steeper drops of 3.4% and 4.5% respectively in the following two days (March 26 and 27). Despite those headwinds, Korean investors showed a particular appetite for leveraged technology ETFs. The ProShares UltraPro QQQ ETF (TQQQ), which offers three times the daily return of the Nasdaq 100, was the most popular buy with $138.5 million in net purchases—a clear bet on a rapid tech rebound. They also bought heavily into the Invesco Nasdaq 100 ETFs (QQQM and QQQ) and Tesla, which saw $10.42 million in net buying even as its stock price had tumbled nearly 20% year-to-date by March 27.
The story wasn’t all about buying, though. Some stocks saw significant net selling by Korean investors. Micron, for instance, recorded a 17.2% price drop between March 19 and 25, and Korean investors responded with $19.93 million in net sales. According to local reports, the sell-off was driven in part by concerns over Google’s newly announced TurboQuant technology—a memory optimization tool that, according to Google’s March 24 blog post, could reduce memory usage by a factor of six. The potential for such a technology to disrupt demand for traditional memory chips clearly weighed on sentiment.
Other notable net sales included Palantir Technologies ($11.242 million), the stablecoin issuer Circle Internet Group ($7.301 million), and semiconductor giants AMD and TSMC. Even the iShares 0-3 Month Treasury Bond ETF (SGOV), a popular ultra-short-term U.S. Treasury vehicle, saw $4.455 million in net selling as investors moved out ahead of a key dividend date in early April.
Still, there were flashes of optimism—and opportunism—in the trading patterns. Lumentum Holdings, a company specializing in optical communication components, saw $50.41 million in net buying after Nvidia invested $2 billion and the stock was added to the S&P 500 on March 23. The company’s shares hit an all-time high on March 24, though they quickly corrected 12.4% in the following days. Similarly, Tower Semiconductor, an Israeli foundry company, entered the top 10 net buys for the first time as its stock soared 70.7% from March 7 to 25 before slipping 8.9% over the next two days.
Rocket Lab, a space launch company, also caught the attention of Korean investors, who bought $43.09 million worth of shares. After peaking at $96.30 on January 16, Rocket Lab’s stock has since settled around $60, reflecting the volatility that’s become commonplace in growth sectors.
Interestingly, Korean investors also placed big bets on their home market via the Direxion Daily South Korea Bull 3X ETF (KORU), which tracks the MSCI Korea 20/50 Index at triple leverage. KORU saw $38.17 million in net buying, suggesting strong confidence in a rebound for the Korean stock market. This is notable given that domestic leverage limits restrict Korean ETFs to 2x, so investors seeking higher risk and reward have increasingly turned to U.S.-listed products.
On the flip side, the Direxion Daily Semiconductor Bull 3X ETF (SOXL), which tracks the ICE Semiconductor Index at triple leverage, saw the largest net selling at $358.40 million. With SOXL stuck in a narrow trading range and failing to mount a significant rebound, Korean investors trimmed their positions for the second week in a row.
It’s a whirlwind of numbers, but the underlying theme is clear: the AI chip race, global geopolitical tensions, and rapid-fire technological innovation are creating both anxiety and opportunity on Wall Street. As Micron and its peers navigate supply shortages, new competition, and a jittery market, investors—whether in Silicon Valley or Seoul—are recalibrating their strategies, sometimes by the hour. For now, the only certainty is that volatility is here to stay.
As the dust settles, all eyes remain on Micron and the broader tech sector, with investors watching for signs of stabilization—or the next big move.