SoundHound AI is one of the most expensive stocks in the artificial intelligence industry right now -- it's even pricier than Nvidia.SoundHound AI (SOUN 3.37%) is a specialist in conversational artificial intelligence (AI). Some of the biggest brands in the world have adopted its software, propelling its stock to gain more than 835% in 2024. But it hasn't performed so well in 2025, with a 21% decline so far.SoundHound's momentum faded after investors learned that Nvidia (NVDA 3.52%) sold its entire stake in ...