Nvidia shares fell more than 6% after Monday’s 4.3% decline, briefly allowing Microsoft to reclaim its position as the world’s second-most valuable company for the first time since June 2025. Microsoft overtook Nvidia to become the world’s second-most valuable company on Tuesday as the chipmaker’s shares plunged amid concerns over the artificial intelligence (AI) outlook and. Microsoft shares were down 0.4 per cent at USD 543.