Alphabet Inc shed $100 billion in market value on Wednesday after its new AI chatbot provided inaccurate information in a promotional video and a company event failed to surprise, increasing worries that the Google parent is falling behind rival Microsoft Corp.

Alphabet shares slid 9% during regular trading, with volumes nearly three times the 50-day moving average. They reduced losses after hours and were roughly flat. The stock had erased 40% of its value last year but soared 15% since the beginning of this year, excluding Wednesday's losses.

Reuters was the first to point out an error in Google's advertisement for chatbot Bard, which debuted on Monday, about which satellite first took pictures of a planet outside the Earth's solar system.

Google has been worried after OpenAI — a startup Microsoft is backing with around $10 billion — introduced ChatGpt software in November.

Google's live-streamed presentation on Wednesday morning did not include details about how and when it would integrate Bard into its core search function. A day earlier, Microsoft held an event touting that it had already released to the public a version of its Bing search with ChatGPT functions integrated.

Bard's error was discovered just before the presentation by Google, based in Mountain View, California.

"While Google has been a leader in AI innovation over the last several years, they seemed to have fallen asleep on implementing this technology into their search product," said Gil Luria, senior software analyst at D.A. Davidson. "Google has been scrambling over the last few weeks to catch up on Search and that caused the announcement yesterday (Tuesday) to be rushed and the embarrassing mess up of posting a wrong answer during their demo."

Microsoft shares surged around 3% on Wednesday and were flat in post-market trading.

Alphabet posted a short GIF video of Bard in action via Twitter, promising it would help simplify complex topics, but it instead delivered an inaccurate answer.

In the advertisement, Bard is given the prompt: "What new discoveries from the James Webb Space Telescope (JWST) can I tell my 9-year old about?" Bard responds with a number of answers, including one suggesting the JWST was used to take the very first pictures of a planet outside the Earth's solar system, or exoplanets. The first pictures of exoplanets were, however, taken by the European Southern Observatory's Very Large Telescope (VLT) in 2004, as confirmed by NASA.

"This highlights the importance of a rigorous testing process, something that we're kicking off this week with our Trusted Tester program," a Google spokesperson said. "We'll combine external feedback with our own internal testing to make sure Bard's responses meet a high bar for quality, safety and groundedness in real-world information."