IonQ (IONQ +4.26%) has consistently surpassed expectations this year. Most recently, it reported $39.9 million in revenue in the third quarter of 2025, which was 37% more than the top end of the expected range and 222% year-over-year growth.

Given the recent results and the growth potential of the quantum computing industry, you may be wondering if now is a good time to invest $500 in IonQ. While it’s exciting to invest in new technologies, we also need to put IonQ’s numbers in perspective.

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IonQ’s valuation is a cause for concern

IonQ is worth $17.6 billion as of Dec. 17. With trailing revenue of $79.8 million, its price-to-sales (P/S) ratio is 154. That’s par for the course with pure-play quantum computing companies (D-Wave Quantum is trading at 308 times trailing sales, and Quantum Computing at an astronomical 2,940 times sales), but extremely high compared to most tech stocks.

Even artificial intelligence (AI) stocks that have skyrocketed in value, including Nvidia and Broadcom, are trading at less than 30 times trailing sales, and many are under 20. For IonQ to be more reasonably valued, it would need revenue approaching $1 billion — a figure the company has projected it will reach in 2030.

Today’s Change

(4.26%) $1.98

Current Price

$48.42

This doesn’t necessarily make IonQ a poor investment. It’s one of the leading companies in an industry that could generate $198 billion in revenue by 2040, according to analysis by McKinsey. But it does make IonQ a risky investment, so you shouldn’t overcommit to it.

With that in mind, a $500 investment in IonQ could be an appropriate starting point, depending on the size of your portfolio. A good rule of thumb is to keep your initial positions to 5% of your portfolio, maximum. If you prefer to limit your risk, consider capping that position at 1% or 2% of your portfolio.