Major US stock indexes ended mixed on Wednesday, August 12, with the Dow Jones Industrial Average slipping 0.04% to 53,770.27, the S&P 500 gaining 0.26% to 7,748.50, and the Nasdaq Composite rising 0.54% to 26,588.49.

Large-cap tech stocks mostly declined, with the Vaneck US Technology Mega-Cap Index falling 0.42%. Meta dropped 3.38%, Microsoft fell 2.26%, Amazon and Tesla lost over 1%, Apple and Google declined 0.87% and 0.18% respectively, while Nvidia bucked the trend, surging over 3%. SpaceX also saw a sharp gain of over 9%.

The semiconductor and memory storage sectors were largely in positive territory, pushing the Philadelphia Semiconductor Index up 2.49%. SK Hynix jumped 9.01%, Seagate Technology rose 7.03%, SanDisk gained 5.76%, Micron Technology advanced 4.92%, and Western Digital climbed 3.69%. The Roundhill Memory & Storage ETF (DRAM) increased 7.68%.

Several AI-related stocks also posted strong gains. Cloud computing leader CoreWeave surged over 19% after reporting second-quarter revenue of $25.75 billion, a 112% year-over-year increase that beat estimates. Nebius soared more than 34%, and Super Micro Computer jumped over 19% following a bright earnings and revenue outlook for its fiscal 2027 first quarter.

Optical communication stocks also moved higher. Lumentum rose 13.63%, Credo Technology Group gained 8.26%, Coherent advanced 8.24%, Corning added 5.18%, Applied Optoelectronics increased 2.79%, and Marvell Technology climbed 2.25%.

Popular Chinese stocks traded in the US broadly declined, with the Nasdaq Golden Dragon China Index falling 2.37%. Notable decliners included BOSS Zhipin (down 3.94%), Tencent Music Entertainment (down 3.04%), NetEase, Chagee (formerly known as CHAGEE), Bilibili, and Alibaba (all down over 2%), as well as Li Auto, iQiyi, Baidu, and XPeng (each down over 1%). On the upside, KE Holdings rose 2.77%, Dingdong Maicai gained 1.30%, and Yum China added 0.66%.

International oil prices edged up slightly. Light sweet crude for September delivery on the New York Mercantile Exchange rose 7 cents to settle at $83.27 per barrel, a gain of 0.08%. Brent crude for October delivery on the London ICE Futures Exchange also added 7 cents, closing at $88.98 per barrel, up 0.08%.

Regarding Middle East tensions, Iran's Persian Gulf Strait Authority stated on Wednesday that US officials' repeated claims of the Strait of Hormuz being reopened do not change the facts. The Strait remains closed and will not reopen unless the US accepts Iran's conditions, according to a report from China Central Television.

Mild inflation data alleviated rate hike concerns, leading to gains in precious metals futures. London spot gold briefly traded above $4,440 per ounce. COMEX gold futures rose 0.63% to settle at $4,469.00 per ounce, while COMEX silver futures increased 0.92% to $65.53 per ounce.

Data from the US Labor Department on Wednesday showed that the Consumer Price Index (CPI) for July rose 3.4% year-over-year, a slight deceleration from June's 3.5% increase, largely due to continued lower energy prices. On a monthly basis, the CPI rose 0.1%, recovering from a period of decline. Analysts suggest the relatively moderate July inflation data, combined with weak employment figures, gives the Federal Reserve reason to maintain its current stance. "The data came in exactly as expected, and the market reaction was slightly positive because there were fears it could have been worse. The prevailing sentiment is that the Fed is not being forced into a position where it must raise rates," said Robert Pavlik, a senior portfolio manager at Dakota Wealth Management in Fairfield, Connecticut.