Shares of Quantum Computing Inc. (QUBT) plunged over 10% in pre-market trading on Monday, underperforming the broader market. The significant selloff comes amid a warning from a prominent investor urging caution around investing in the quantum computing company.

According to reports, a top investor cautioned against investing in Quantum Computing, advising others to steer clear and "don't come within 500 feet" of the stock. While the company has been at the forefront of the recent surge in quantum computing stocks, fueled by the technology's immense potential, concerns about the stock's valuation and sustainability of the rally appear to be weighing on investor sentiment.

The plummet in Quantum Computing's stock price was further exacerbated by concerns about increased competition in the artificial intelligence (AI) space from Chinese startup DeepSeek. The company's AI chatbot recently surpassed ChatGPT as the highest-rated free app on Apple's App Store, sparking fears that its more efficient and cost-effective models could pose a threat to established AI players and, by extension, quantum computing companies that are often seen as symbiotic with AI systems.