[charlief]

Regarding: "Adobe's shares rise as much as 17 percent"

Just a small detail, but the above bullet exaggerates the indicative reaction of the market. It was up 17 percent for an instant because someone fat fingered and bought it for $30.00 exactly at 3:08pm (Added: 12 minutes after the announcement at 2:56pm), maybe a little excited to buy in. Really it is up 10-11%, which is a strong and positive reaction, but there is more uncertainty factored into the price than what the bullet would seem to imply.

[zokier]

Gotta love stock markets. A rumor arises of two CEO's secretly meeting, and stocks skyrocket instantly. I'd assume that nobody actually knows what they were discussing, if they even met. Wouldn't be much of a secret meeting otherwise.

[joezydeco]

Proves the old adage. "Buy on the rumor, sell on the news"

[narkee]

It's really interesting, when you think about it as a system that changes in response to observation.

Can you imagine if physical systems worked like that? That observed physical phenomena would change in response to what the experimenter/observer thinks will happen?

[pmichaud]

Yeah, that's sort of what actually does happen.

[narkee]

I should have been more precise when I said observation. In QM, clearly scientific "observation" acts on the system, causing the system to "collapse" into a definite state, but what I meant by observation in my previous comment was that speculative observation, commentary and opinion can affect the state of the system.

That is clearly not true for physical systems.

[ThomPete]

It kind of do according to QM.

[narkee]

Not really. QM measurements follow probability distributions, but are not dependent on what the experimenter thinks about the system.

Consider a 2-state single particle system, the outcome probabilities of one state vs. the other are fixed by the Hamiltonian and the time evolution of the system, and not by the experimenter's opinion of the system.

[eogas]

Time to short sell then?

[mcknz]

indicative reaction of the HFT algos -- ahem, I mean Waddell & Reed.