LONDON -- Nvidia has lost its briefly worn crown as the world鈥檚 most valuable listed company after its stock plunged almost 13 per cent in the past week.

The U.S. chipmaker鈥檚 market capitalization hit US$3.34 trillion on June 18 to surpass Microsoft鈥檚 but has since shed US$430 billion. Now worth US$2.91 trillion, Nvidia has fallen into third place globally, behind Microsoft and Apple, which have a market cap of US$3.33 trillion and US$3.19 trillion respectively.

Shares in Nvidia tumbled 6.7 per cent Monday, marking its third-straight day of declines and signaling that investors鈥 excitement over the crucial role the company is expected to play in the artificial intelligence revolution may be cooling after eye-popping gains in the stock.

鈥淲hile we do believe in AI, there have been signs of overexuberance in the U.S. market over the last month,鈥 Jim Reid, a research strategist at Deutsche Bank, wrote in a note Monday.

On Tuesday, shares of Nvidia climbed more than 5 per cent higher, reversing course after its multi-day sell-off.

Nvidia鈥檚 stock has been on a tear, soaring almost 139 per cent over the past year. The company鈥檚 chips power AI systems, including generative AI, the technology behind OpenAI鈥檚 ChatGPT that can create text, images and other media.

鈥淲hat we see with Nvidia is typical volatility, which is expected when a stock rises as quickly as Nvidia鈥檚 did,鈥 Jochen Stanzl, chief market analyst at trading platform CMC Markets, told CNN. 鈥淎 lot of good news has been priced in. Now investors have started to take profits and they seem to prefer selling stocks with the best year-to-date performance.鈥

Market contagion?

Frenzy around the potential for AI to radically change the way we live and work 鈥 and make big returns for investors 鈥 has driven much of the stock market鈥檚 returns over the past year and a half.

Nvidia is a member of the so-called Magnificent Seven, the mega-cap tech companies whose shares greatly outperformed the broader U.S. stock market rally last year. The S&P 500 index climbed 24.2 per cent over 2023, compared with the average 111 per cent rise in the stocks of the Magnificent Seven.

In a note published Monday, Deutsche Bank noted that, as a result of the seven stocks鈥 dominance, 鈥渢he U.S. stock market is close to being the most concentrated in history.鈥 On Tuesday, the bank wrote that the decline in Nvidia鈥檚 stock the previous day had 鈥渉eld down U.S. equity returns more broadly.鈥

The S&P 500 closed 0.3 per cent down Monday, while the tech-heavy Nasdaq dipped 1.2 per cent.

However, Derren Nathan, head of equity research at investment platform Hargreaves Lansdown, isn鈥檛 too worried about contagion.

鈥淎lthough Nvidia has sneezed, the wider market hasn鈥檛 caught a cold, with a mixture of less extreme movements in both directions for the rest of the Magnificent Seven,鈥 he wrote in a note Tuesday. 鈥淢eanwhile, in other sectors, U.S. stocks saw gains (Monday) in energy, financials and utilities: a vote of confidence by investors in the health of the broader economy.鈥