If it's news on a major website, it's priced in. So yes, we know it is priced in.
Obviously, it wasn't news 5 years ago, so no it wasn't then.
There is a gray area which is where professional investors who have an informational advantage make their money. But by the time something is mainstream news, that gray area is long gone.
CEG jumping 20% on the MSFT deal means it isn’t all priced in imo. Everyone has known there are rising energy needs and had bid up CEG. Then the Three Mile Island restart news hit and apparently it wasn’t already priced in
Nobody (well the market) expected Nvidia's revenue to start growing exponentially, though. Now it's forecasted to grow by at least 20% per year for the next 3 years. So presumably everything above that is not priced in.
Actually people did expect that, which is why the market does not accurately "price things in." People working in ML, Cuda, ~GPT2 were pretty confident in the eventual impact of AI and knew of Nvidia's monopoly on it.
There's a sort of midwit meme here where the naive take "oh this company is going to sell more next year, i should by stock at whatever price", -> "no, everything's already priced in" -> "if everything was priced in, you'd see a historic price graph as a straight line with a slope of interest rates"
> You don’t know if it’s priced in. Was it priced in 5 years ago?
It wasn't priced in 5 years ago, that is the point today it is priced it, people expected this. You should have bought when Microsoft invested billions in them 2019, today more investments like this are expected once these investments stop NVIDIA stock will drop since they were expected.
So saying now is the time to invest is dead wrong, NVIDIA is currently priced as if these investments will continue to ramp up so these things are already priced in. Only idiots thinks "positive event -> I must buy stocks!", no if the positive event was expected then the stocks wont move, if a positive event was expected but didn't happen then stocks go down, that is the situation we are in currently with NVIDIA.
How do you know it was priced in? You look at what people say they expect, and this is what people say they expected, hence we know it was priced in.
What if I were to tell you Nvidia's monopoly and the implications of AI were obvious many years ago? Many people on HN bought large amounts of Nvidia stock a while ago. Karpathy's "Software 2.0" was widely read here predating much of Nvidia's market cap increase:
It was "obvious" C3.AI was not a real AI company worth much. The market still "priced in" at $18 billion for months: https://finance.yahoo.com/quote/AI/
Obviously, it wasn't news 5 years ago, so no it wasn't then.
There is a gray area which is where professional investors who have an informational advantage make their money. But by the time something is mainstream news, that gray area is long gone.