Yes but how do you know it is AAPL that should move up and not (say) TSLA that moved the index in the absence of market moving news.
I don't. All components in an index get repriced based on the overnight futures move. It might only be temporary, majority of the time it is, but program buys or sells take place automatically. Futures against stocks. One gets bought, one gets sold till they get "balanced".
%% I though SPY was 505, now , but cant keep up with all those details. Have to factor in also ; bid\ ask, derivatives, dividends, HILL\C is right\both + then the combo; for SPY=liquidity leader. I never trust some of the S&P indexes that show no volume
Perfect explanation, i used to look at lot at NASDAQ too and the heat maps of what was moving it most and how
%% SPY is still below 200dma= bear down market, as of 12;11 CST+ if you like close prices + i do still a bear for yesterdays close. My comments dont apply to rest of Fed day, even though i usually record close price any day. Good points on SPY+ USa benchmark, but i do some SPXS+ spxu also ; but Dow, DIA, sdow, QQQ + IWM are helpful hints on USa market also .
Well, it looks like you got the future all figured out, So go out there into the big, bad, market and make a Million dollar Turtle,
%% OK; but i don't make market predictions. Maybe a forecast based on 200dma[ bear trend, SPY] + stuff. MacBookPro ; i'm rereading again a book = The RULE by Larry ''Mint '' Hite.....................