Do stock upgrades made by websites like Yahoo finance have any

Sorry, I had a brain fart and forgot market efficiency.

So new question:

I remember this graph from one of my classes about how fast stock market prices changed after news from cnbc is released in just a few minutes.

Would it be realistically possible to somehow write a program that instantaneously buys and sells stock at a certain stop price based on its average volatility and volume to make a quick profit? Would broker websites be able to do these transactions this fast?

>>1024311
stock upgrades/downgrades by research firms (not yahoo) do often materially affect the price of stocks, particularly if they're from reputable analysts.

>>1024331
yes, stocks react to news. what you are asking is basically not possible, there are firms that read the news with computers (look up Machine Readable News), processing the news at light-speed then executing trading strategies set by traders based on what they thought the news might contain. Anything high-speed in finance is going to take a LOT of investment capital to just get a strategy going if you want to play those games. These MRN news services alone are like 20k/year, doesn't count any exchange fees, computers, software, or co-location fees that you would need to pay.

>>1024331

I feel like what you're talking about is totally doable. All it would require is an algorithm that automatically sells/buys when a stock goes above/below its Std of risk.

Still very fallible -- it would have to be much more complicated than that.