Many artificial intelligence (AI) stocks have generated great returns for investors over the past year. But along the way, that has resulted in some stocks reaching absurdly high valuations. In some cases, investors are paying massive premiums for future growth.

High valuations may sometimes be warranted, but in some situations, the premium investors are paying may simply be far too high, putting them at risk for corrections down the road. Three of the most expensive AI stocks to own right now are Nvidia (NASDAQ: NVDA), SoundHound AI (NASDAQ: SOUN), and MicroStrategy Incorporated (NASDAQ: MSTR). Are these shares worth their inflated valuations, or is it time to step away from these high-priced stocks?

1. Nvidia

Chipmaker Nvidia has been symbolic of AI's meteoric rise in popularity over the past year. At more than $2 trillion, the stock's market cap has soared to new heights. And unsurprisingly, investors are paying a big premium for a piece of the business.

At 36 times the company's trailing revenue, this highly coveted AI stock doesn't come cheap. The bad news for value investors is that it may not get any more affordable as Nvidia has remained a hot buy this year, rising around 80% in value since the start of January.

For fiscal 2024, which ended on Jan. 28, the company's revenue soared by 126% to just under $61 billion while posting profits of nearly half that -- $30 billion. If Nvidia can continue growing at such an incredible pace and keep up an impressive profit margin, it could still look like a cheap buy when bought for the long haul. In Nvidia's case, the AI stock could still be well worth its high valuation.

2. SoundHound AI

Shares of SoundHound AI took off earlier this year after investors learned that Nvidia has invested in the AI business. SoundHound uses AI to enable conversational experiences, such as in drive-thrus to expedite and improve the ordering process for customers. There's significant potential there, but this is still a bit of an unproven business, with SoundHound reporting $46 million in revenue last year and its net loss nearly doubling that tally, totaling a negative $89 million.

SoundHound hasn't proven it can be profitable, and investors are taking a leap of faith with the business, largely, it appears, on the hopes that Nvidia is right and that it has found a promising AI business to invest in. At $2.5 billion, SoundHound's market cap isn't large, but given its relatively modest revenue, investors are paying a multiple of 45 times its trailing revenue.