If you followed my posts of yesterday you will have noticed 12555 a couple of times. If a level seems important to me, it usually remains "important" for sometime.
Now, yesterday the market opened at 12389 and today the high was 12692. The second high was 12690 and after that we went lower. On an intraday timeframe one could consider this to be a double top. Next the difference between those two levels is 303 points, the average price level is 12540. Price likes going back to the midpoint of extremes...
I also pay attention to the average true range of the last 10 bars on a 5-minute timeframe, that is around 15 lately. When price bounces off or from a certain level, the reaction is usually about the average range. This gives us 12540 +/- 15 = 12555 or 12525.
All of this number crunching is just an excuse
Seriously, just look at the chart and look where price found support yesterday. Price reacted strongly on the upper line. I wonder if Mr. Marcus would've said everything is known in advance.