"I've been trying to get Yahoo! Finance to fix a huge problem they have with the volume data that is displayed on their charts," a reader recently wrote. "They have been displaying bad volume data for as long as I can remember and, so far, they have refused to admit it or fix it."

As an example, the reader suggested I go to the Yahoo! Finance website and pull up the 3-month chart for the NASDAQ index. "This page will display the daily price and volume for the NASDAQ Composite Index," the reader explained. "If you look at the volume data at the bottom of the chart you will see that the typical volume ranges between 10 million and 20 million shares. This is incorrect by a factor of 100. The actual NASDAQ Composite volume for a typical day ranges between 1 billion and 2 billion shares."

The reader had a number of other examples he could point to. "Go to the Yahoo! Finance opening page and note the 'Market Summary' block on the left," he wrote. "Look at the link for NYSE Volume. This is the daily volume for the NY Stock Exchange and has a typical value of 1-3 billion shares. Yahoo displays this value correctly here. But now click on the link to go to the detail page. Note here that the index value and the chart volume are NOT displayed correctly, they are now showing a range of 1-3 million shares. Do the same for the link to the S&P 500 INDEX. The 3-month chart shows a range of 10-30 million shares, which is obviously not the case."

Obviously, Yahoo is suffering from a bug or two here, and you'd think they could fix things in a jiffy once someone complained. But the reader has been persistently asking Yahoo to do something about it for well over a year, and has been met with total indifference. "When I first e-mailed Yahoo about this they tried to blame their data provider, Commodity Systems, Inc., for the problem. I contacted CSI and explained the situation, and they explained to me that they only provide a raw data stream and that it is the user's responsibility to properly scale the data. In short, they said it was Yahoo's problem. I relayed this information to Yahoo and they said they would pass the information on to engineering. This correspondence took place in October 2004, and to this date they still haven't fixed the problem."

Since Yahoo probably can rectify this in five minutes once somebody with a little bit of authority there decides it ought to be done, for the record let me just state that my reader clearly knows whereof he speaks. Looking at the links he cited as they appear very early today, the share volume tick for yesterday (December 8, 2005) on the 3-month Nasdaq shows it just short of 20 million, whereas the actual Nasdaq share volume yesterday was 1,988,391,000 - or 1.99 billion -- shares. (In dollar volume, that would appear to represent a mistake of $40 billion or so.) Volume on the NYSE yesterday was 2,211,524,000 shares, but the NYSE volume page shows the "Index Value" as 2,211,524.00, a mere 2.2 million.

Let's just hope no one is making investment decisions based on these figures, and that Yahoo does find all the bad numbers when it finally bestirs itself to fix them. "These examples are not isolated incidents," the reader writes. "I have found incorrect volume data displayed on many of the charts. It looks like Yahoo has a problem with any high-volume indexes that trade upwards of a billion shares per day. How can such a high-profile website get away with providing the world with bad data for so long?"