difference between NYSE volume reported by esignal and yahoo

[chud]

I've noticed that there's a big difference between NYSE volume as reported by Esignal ($TVOL) and as reported by Yahoo. What accounts for this?

I was thinking that maybe Esignal is only counting volume for NYSE that is traded through the NYSE itself and doesn't add the shares traded on ECN's maybe?

Thanks for answers.

[checkraise]

As of 10:25 on 3/6/07 $TVOL on eSig showed 388,056k while nyse.com reported 754,307k in volume.

[chud]

Anybody from eSignal know an explanation for this?


Thanks.

[dragan]

total volume

eSignal $TVOL represent total volume of NYSE listed stock.
www.nysedata.com

Yahoo total volume represent total volume of
NYSE listed stock + ARCA + regional stock exchange.