ARCA and AUTO.....in my limited and perhaps wrong perception are not really MMs at all. They are electronic trading platforms through which all traders who are not trading through the routinely-listed MMs for any given security are routed.
You can see free Level II list of MMs on IHUB with 15 minute delay. Or you can go to www.otcbb.com.
So, because I trade with TDWaterhouse and TD is not listed as a regular MM for CBAI, TD would have to route my CBAI trades through ARCA, AUTO, or some other MM with whom they have an arrangement to handle their trades.
In the case of CBAI, ARCA is currently sitting well below the bid and also well above the ask, so not sure of its current (today) relevance to CBAI at all.
From what I can see, when a run or a drop starts, ARCA and/or AUTO often suddenly appear with large blocks to buy or sell. They may be reflecting many retail traders whose broker or trading platform has to get routed through ARCA or AUTO.
Both ARCA and AUTO usually only appear on the MM board during trading hours, and disappear otherwise. I assume they are representing orders that are "good for the day".
So I would not describe ARCA as the measure of all things but it is often a current indicator of a short-term trend. Sometimes, very short-term.
I stand to be corrected.
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