Today's one thing is, "Hoo-boy."

Remember that stock market high back in September, way back on September 18? No, wait September 19. That was it, September 19.

You could be forgiven for forgetting. A four-week long drop followed it pretty quickly. Half of the drop's loss was produced during its last week.

The past 2-1/2 weeks have trended straight up. Not in a straight line actually. Well, yah, pretty much a straight line up. There was no time to think of vague prior highs, not with the memory of recent lows still so clear. Especially not when the focus is on the Fed shutting off its liquidity spigot that has produced the multi-year bull run.

Anyway, I have news. As if the recent rally wasn't already packed with big up-days, now it can include a big up-night. Thanks to the Bank of Japan not following the Fed's lead -- and expanding its own QE program -- last night's trading surged through September's prior high. Dow futures were ahead more than 240 points at their high.

Hoo-boy.

How many investors were so recently thinking for the umpteenth time, if only they had the opportunity to sell that they had had just a couple of weeks earlier. Well, wish come true, right? 

If you think this sudden return to those price levels will remind them of their earlier sentiment... you may be right, about some of them. It's a little more complex than that. Those who sold nearer to the bottom probably haven't yet bought back, and those who held firmly probably already added.

Monitor the opening hour, at least its end. Comparing it to the opening levels should give an accurate impression for how this sudden paradigm shift of new highs is going to be accepted. Or, rejected.

Filter THIS! …is a missive that tells you one thing, the most important thing, if you had to filter your view of today's marijuana stocks price action through just one thing -- okay, sometimes two -- what would that one thing be?