agree...10-11:15am is the best timeframe. Add 9:40-10am, for experienced traders. Most post-11:30am markets are slow chop, like today, yesterday, etc.
Verify: Look at the last 3 months worth of daily COMPQ charts, and mark out where the biggest runs, moves occurred, each day...then tabulate, by morning vs afternoon, and day of week.
You should find 70%+ of large moves occurred in the morning, before 11:15am, this last few months. This has been the case for a long time. I like trading the open.
and sure, you Could trade all day long, but why? I think the best-odds high-volatility moves occur primarily in the first half of most days, most of the time.
ken