--- title: "U.S. stock market midday update: Aehr Test Systems down 15.56%, frequent insider selling triggers market confidence crisis" type: "News" locale: "en" url: "https://longbridge.com/en/news/286802309.md" description: "Aehr Test Systems fell 15.56%; Applied Materials fell 5.41%, with a transaction volume of USD 1.815 billion; ASML fell 2.21%, with a transaction volume of USD 1.545 billion; Lam Research fell 2.84%, with a transaction volume of USD 1.041 billion; KLA fell 2.74%, with a market value of USD 228.9 billion" datetime: "2026-05-18T17:17:43.000Z" locales: - [zh-CN](https://longbridge.com/zh-CN/news/286802309.md) - [en](https://longbridge.com/en/news/286802309.md) - [zh-HK](https://longbridge.com/zh-HK/news/286802309.md) --- # U.S. stock market midday update: Aehr Test Systems down 15.56%, frequent insider selling triggers market confidence crisis **U.S. Stock Market Midday Update** Aehr Test Systems fell 15.56%. Based on recent key news: 1. On May 13, Director Howard T. Slayen sold 6,819 shares of Aehr Test Systems common stock at a price of $104.73 per share. This transaction raised concerns in the market about insider selling, leading to a decline in stock price. Source: EDGAR system 2. On May 14, CFO Chris Siu sold 470 shares of common stock at a price of $108 per share, and also sold 1,600 shares through a trust at a price of $106.78 per share. These transactions further intensified negative sentiment in the market regarding executive stock sales, causing the stock price to remain under pressure. Source: EDGAR system 3. On May 15, the market's reaction to frequent stock sales by company executives led to a decline in investor confidence and a drop in stock price. Source: EDGAR system. The U.S. stock market has recently experienced increased volatility, and risks need to be monitored. **Stocks with High Trading Volume in the Industry** Applied Materials fell 5.41%. Based on recent key news: 1. On May 18, Morgan Stanley downgraded Applied Materials' rating from Overweight to Equal Weight, resulting in a 3.2% drop in stock price. Morgan Stanley pointed out that concerns over market share loss in China and valuation discounts compared to peers were the reasons for the downgrade. 2. On May 18, UBS raised the target price for Applied Materials from $480 to $515, maintaining a "Buy" rating. This move reflects the market's optimistic expectations for Applied Materials' future growth, despite short-term stock price fluctuations. 3. On May 16, Tiger Global Management increased its stake in Applied Materials to 1.7 million shares, indicating enhanced confidence from institutional investors in the company. This move could have a positive impact on the stock price. The semiconductor industry is experiencing strong demand, driven by AI growth. ASML fell 2.21%. Based on recent key news: 1. On May 17, ASML signed an agreement with Tata Electronics to invest $11 billion in building India's first 300mm wafer fab, focusing on automotive electronics and AI chips. This move highlights India's increasing importance in the global semiconductor supply chain, driving fluctuations in ASML's stock price. Source: Jin10 Data 2. On May 17, Indian Prime Minister Modi and Dutch Prime Minister jointly witnessed ASML and Tata Group signing a memorandum of understanding to deepen semiconductor manufacturing cooperation, further promoting the development of India's semiconductor industry. Source: Jin10 Data 3. On May 17, global semiconductor supply and demand changes, with India accelerating its entry into the semiconductor manufacturing market, challenging the dominance of Taiwan, South Korea, and China, affecting ASML's market expectations. Source: Bloomberg. Competition in the semiconductor industry is intensifying, and policy changes should be monitored. Lam Research fell 2.84%. Based on recent key news: 1. On May 18, market analysis showed that Lam Research Corporation was not included in the list of five stocks recommended by top analysts, despite its rating being moderate buy, which may lead to insufficient investor confidence and a decline in stock price. Source: MarketBeat 2. On May 18, analysts pointed out that Lam Research Corporation's DRAM market share is low, and its growth rate is expected to slow down by 2027, which may affect investors' expectations for its future growth. Source: MarketBeat 3. On May 18, Lam Research Corporation's stock price closed at $284.72, with analysts holding a neutral stance on its future performance, and no significant positive news to drive the stock price up. Source: MarketBeat The semiconductor industry's growth expectations are slowing down, and there is a noticeable outflow of funds. **Stocks ranked among the top in industry market capitalization** KLA Corporation, down 2.74%, with a market capitalization of $228.9 billion, trading volume increased, and there has been no significant news recently. Trading is active, and fund flows are evident. Considering the sector and industry trends, this stock shows significant volatility, and the specific reasons need further observation ### Related Stocks - [AEHR.US](https://longbridge.com/en/quote/AEHR.US.md) - [AMAT.US](https://longbridge.com/en/quote/AMAT.US.md) - [ASML.US](https://longbridge.com/en/quote/ASML.US.md) - [LRCX.US](https://longbridge.com/en/quote/LRCX.US.md) - [KLAC.US](https://longbridge.com/en/quote/KLAC.US.md) ## Related News & Research - [If You Can Only Buy 1 AI Stock for the Rest of 2026, Make It This One](https://longbridge.com/en/news/286943708.md) - [Baader Bank Aktiengesellschaft Decreases Position in Lam Research Corporation $LRCX](https://longbridge.com/en/news/286524495.md) - [iA Global Asset Management Inc. 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