Does ARCA still use the same order logic that it used to? I bought a stock through ARCA and paid 18.75, while the market was right around 18.67. I even checked time and sales, and my trade of 18.75 was surrounded by a bunch of trades around 18.67-18.68. I would think that I would get the best price, whether it had to go to another ECN, a market maker, or whatever.
Are you speaking theoretically, or in practice? Is it supposed to use smart routing, but doesn't do the job it's supposed to?
ARCA is not as good as before, do not get the best fill. I have had ARCA order locked with ISLD & do not get filled. The only thing I can do is trying to use other routes as much as possibe.
They no longer have a "Best Fill" policy so can now trade through other ecn's prices. To prevent that happening use a smart routing if your system has it. If it doesn't, PM for another idea.
Arca is good for shorting, can place order on a downtick and the software will automatically place it .01 higher than best bid. Supoose only takes 100 sh at .01 up, will take rest at your limit price or better after bid tiks up. Although i use island for everything else, longs and shorts where bid is already uptik.