Global stock markets experienced declines on Wednesday, with European and Asian shares falling, as oil prices surged more than 2% following U.S. strikes on Iran. The tensions escalated after attacks on three ships in the Strait of Hormuz.

Brent crude, the international benchmark, rose 2.2% to $75.80 a barrel, and U.S. benchmark crude increased by 2.1% to $71.94 a barrel. These prices represent a recent recovery to levels seen before the conflict with Iran began in late February.

The heightened geopolitical activity has introduced uncertainty into oil price fluctuations, which had previously fallen from peaks above $100 during the war. This volatility occurs concurrently with concerns that the fervor surrounding artificial intelligence (AI) stocks may have inflated their prices beyond the actual productivity gains expected from substantial investments in computing power and data centers.

"As such, geopolitical headlines will likely determine market sentiment over the coming hours," Ipek Ozkardeskaya of Swissquote noted in a commentary. "A further deterioration in the situation could weigh further on equity valuations along with rising stress in technology."

In European share trading, Germany's DAX lost 1.1%, the CAC 40 in Paris fell 0.9%, and Britain's FTSE 100 slid 0.8%.

U.S. stock futures showed a similar trend, with the S&P 500 futures edging 0.1% lower and Dow Jones Industrial Average futures down 0.4%.

Asian markets also saw significant downturns. Tokyo's Nikkei 225 dropped 2.1%, and the Kospi in South Korea shed 5.4%. The South Korean index had experienced a sharp rise and subsequent fall, briefly exceeding 9,000 points last month before facing heavy selling pressure in major AI-related tech stocks such as Samsung Electronics and SK Hynix. Samsung's shares fell 6.3% early Wednesday, adding to a roughly 7% drop the previous day, while SK Hynix reversed early gains to fall 5.7%.

Conversely, Taiwan's Taiex rose 0.6%, and Hong Kong's Hang Seng climbed 3%. Shares of Chinese AI model startup Zhipu, also known as Z.ai, saw a nearly 14% increase on Wednesday, following its $558 million trading debut in January. A six-month lock-up period for cornerstone investors was set to expire this week, though reports indicated that nearly 70% of these investors intended to remain with the company, countering earlier concerns of a potential sell-off.

The Shanghai Composite index declined 0.5%, while Australia's S&P/ASX 200 shed 0.2%, and India's Sensex lost 0.7%.

On Tuesday, a downturn in AI stocks contributed to a broader decline on Wall Street. The S&P 500 fell 0.4%, the Nasdaq composite dropped 1.2%, and the Dow Jones Industrial Average decreased by 0.2%.

Several technology companies experienced notable stock price drops, including Advanced Micro Devices, which sank 6.5%, Intel, which shed 9.7%, and Micron Technology, which lost 4.7%. SpaceX, the parent company of xAI, saw its shares fall 6.8% on its first day of trading after being included in the Nasdaq 100 index.

Electric vehicle company Rivian Automotive dropped 18.1% after announcing plans to sell 75 million shares, a move expected to dilute the ownership stakes of existing shareholders.

In currency markets, the U.S. dollar rose to 162.26 Japanese yen from 162.11 yen, and the euro climbed to $1.1426 from $1.1414.