(Bloomberg) -- Ever since OpenAI’s ChatGPT lit up the internet in November, companies can't stop talking about artificial intelligence. Take this earnings season so far: References to AI and related terms during calls with investors are already up 77% from a year earlier.

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It's no wonder. AI-hungry investors have propelled Nvidia Corp., which makes the chips needed for complex AI computing tasks, into the best-performing stock among mega-caps this year. Relatively obscure firms with AI in their names have also skyrocketed. BigBear.ai Holdings Inc. has surged more than 300%, while C3.ai Inc. and BuzzFeed Inc. have more than doubled. Guardforce AI Co. is up 51%.

A lot of the companies tossing around the phrase AI are just taking advantage of the hype. Some are speaking aspirationally about how they see AI transforming their businesses — one day, some day. And then there are the real, practical use cases for AI and machine learning that companies have been actively investing in, developing and using — in some cases, long before AI became a buzzword — proving that the power of these algorithms is already reaching far beyond chatbots to change everything from the way companies manage their parts inventories to how they're recruiting for job candidates.

“It is impossible to quantify what the impact of AI could be and equally possible that a wave of enthusiasm carries stocks with expertise in or exposure to AI, no matter how tenuous, higher and higher,” said Russ Mould, investment director at AJ Bell Plc. “All investors can do is stick to their disciplines and focus on competitive position, management, and valuation, while making sure that they truly understand the business, before they put any capital at risk.”