You will notice the "unreachable regional" quotes quite often. More often than not, these quotes are not active. We have the ability to "wake them up" - but rarely are the prices an improvement on the ECN's or the NYSE. I have not noticed any lack of liquidity on the NYSE myself...are you referring to specific stocks??
Don has it right. Most regionals follow the primary market(ie. NYSE). Once in a while there is an arb avialable, but this is often just a "bad" quote that needs updating. Our ROX software has access to the regionals Boston,PSE & Chicago-however, most of these regionals will not honor posted quotes from pro traders. Word to the wise, Trade NYSE stocks on the NYSE and get potential price improvement and a "real" market. Use ISLD or REDI for ECN match's on the NYSE and avoid the regionals. Gene Weissman Lieber & Weissman Sec., L.L.C. gweissman@stocktrade.net