I guess the reason of Amazon's stock going up while Google's stock going down might be that no one expected anything from Amazon/AWS in generative AI space yet,

I guess the reason of Amazon's stock going up while Google's stock going down might be that no one expected anything from Amazon/AWS in generative AI space yet, while everyone already expected Google to launch something like Bard for search engine and when launched, it was not as per market's expectation that had priced the value already. Also, Google has a potential of losing large search market to Bing and thus losing the revenue. While Amazon with this launch does not have the same story, it might (or might not) help them to gain more market in a new space but might not lose the existing ones, at-least not the major revenue source like search for Google.