You've answered your own question. It is all of the above. The price system in any market factors in all of the information and motivations of the participant

You've answered your own question. It is all of the above. The price system in any market factors in all of the information and motivations of the participants, and balances them out with a single value : the price. The killer feature of the freely-trading market is the price. It communicates the state of the market as both an input and an outcome of the actions of the market players. Remember that for any exchange to occur, two things of unequal value have to be exchanged by two willing participants. But the inequality between the items being exchanged is in the eye of the individual holder. The motivations are rarely the same for each participant, so you can never actually make blanket statements about why a market moves where and when it does - very rarely does a single issue dominate a price, because in those circumstances you have a market that stops exchanging if everyone has the same view.