Why is "low volume" important?
Because low means that there were so many sellers at 204 "on the way down" that the buyers were overwhelmed and couldn't handle the deluge of sell orders.
Where a market "DOESN'T TRADE" is more important than where it "DOES TRADE". Why? Because the low-volume areas are where one side of the market is weaker relative to the other. The place where HIGH trades is where the bulls and bears get together and agree on a price. High areas are useful for setting up trades and for referencing market action, but it is the LOW zones that should keep your attention much more finely tuned.
You can risk a tiny amount up here as we test to see if those sellers are still here. The market will take a little while to get through this zone and we can learn a lot about the future of price action by watching what happens here at the 203.50-204.25 level.
At the end of today, a short sale could be setting up, but I won't know until the end of today: What I'm looking for is a trading range smaller than yesterday. If true, then short if "down on the day" tomorrow for risk averse. If you can handle overnight gap risk then short at the close and risk 1 average trading range or roughly 1.5 points. Target 3-4 points in 3-4 days.
10:53AM EST 3/17/2016 203.70 last SPY
this marked is non stop up to around resistance of 2100. I am 75 contracts long into this instruments, which I have been since 1930 a couple of weeks ago....it's been very profitable;) strong resistance around 1960. Have S/Ls wide but fear is wearing off and spring time is comint...oil is stabalizing aroundt 40$ and FEDs keeping the intereaste low...now technical instrument can really argument against all these fundamentals and situation of the market, other than giving a good indication of support and resistance levels. Don't you agree OP?
An idea I posted some days ago;
last days on my new real account btw; https://www.myfxbook.com/portfolio/sharpinvesting/1553534