Quote Originally Posted by Mike View Post
How do you know they are using tape C? If you look at the Nasdaq site I put in the article, you will find that MarketSmith and IBD will show that volume eventually. I don't suggest that I know what they are doing, just that they correct the NASDAQ chart to show "Total Share Volume" from the nasdaq.com Global Market Summary before the next trading day.
Mike you're right IBD's correcting the volume to the figure you've found on the NASDAQ site. After looking again, this does not match the correct number for the NASDAQ Composite (Tape C), perhaps a change since moving to a new data source for the NASDAQ Composite chart on investors.com. The figure displayed on the nasdaq.com link you gave is TAPE A+B+C, which is not the volume for the NASDAQ Composite.

It's confusing because NASDAQ actually facilitates trades in NYSE listed stocks (TAPE A) and old AMEX stocks + ETFs (TAPE B) plus NASDAQ listed stocks (TAPE C). When the NASDAQ boasts of it's volume it's actually talking about how many TAPE A,B,C trades take place either on it's exchanges or facilitated by it's Trade Reporting Facility TRF. This is NOT the NASDAQ composite volume, which is the volume of NASDAQ listed stocks on all venues / TRFs -including NASDAQ's, which is only TAPE C.

Check out this link for more answers, and perhaps PM me if you have any interest to know more.
http://www.wsj.com/mdc/public/page/2....html#nysevolA