The COMP and NDX track really close. The SPX, Dow and OEX track together. Now the two groups are similar, but definitely different.. It vaguely seems from memory, they were tracking better about a month ago, but lately the COMP/NDX tend to do a little more of their own thing compared to the others.
Now the SPX futures are actually considered the over all driver, hence the watching of the PREM which is the difference between the SPX futures and SPX cash and when at extremes can indicate turning points or sudden moves.
The PREM did a local high at 12:26 which was the highest since about 10am. The TICK also spiked up to a local high then. PREM has been sort of downtrending, sidewayish since then. The SPX, Dow and OEX looked to have turned about 12:27.
Could also do a more broad up trend off the 11:51 local low on the PREM and 11:57 on TICK. SPX, Dow and OEX all put in LOD's about 11:58.