The first hour's signs of inertia in the S&P 500 around the 2600.50 open could have restrained any trending attempt Friday. Or, the influence could have doomed a trending attempt to failure. Gapping up to test new highs isn't likely to sit still, and Friday's session did not. So, the inertia signal's latter influence enabled reactions down to 2600.00 after touching a new high at 2603.00.
The morning's 2604.50 bias-up target wasn't tested, and neither was it rejected. But being the product of a shortened-session, it does not become "unfinished business above." It's still likely to be attacked or tested, anyway, while probing above Friday's range, so long as a pullback were to hold 2597.00 (+/- 1 tick). Holidays aren't generally associated with extremes.
No pattern or other objective is currently in-play. Friday's new trend high close doesn't require another, since it was produced by a shortened session. But that doesn't preclude probing a new trend extreme intraday.
Meanwhile, the slightest misstep after trying to extend the rally could result in a sudden drop back to -- and potentially through -- two-week old lows.