Tuesday, June 22, 2010

Warning

I wrote in Quick Takes Pro yesterday that the JNK junk bond ETF scored a death cross as the 50-day average dropped under the 200-day average. A customer challenged my saying that there was no such cross on Stockcharts.com and it was not even close.

Hmmm, I thought. Well, not hmmm but this could be a problem. So, I downloaded eSignal's data (my charting package) and plotted it in excel. Same chart that eSignal itself plotted. Then I drew the same chart in Barchart.com and Bigcharts.com and they both agreed with eSignal.

How many people use Stockcharts? Rhetorical question. The answer is plenty. Are they trading off this discrepancy? Trust nothing and if you can afford it, buy two systems.

Stockcharts, if you are reading this I used to do this sort of chart checking for a living for Tradecenter and then Knight-Ridder Financial (their buyer).

5 comments:

Amit said...

Thanks for the headsup.

Here is the odd part, if one uses a larger period on yahoo or google finance, the cross-over does not happen.
http://www.google.com/finance?chdnp=1&chdd=1&chds=1&chdv=1&chvs=Logarithmic&chdeh=0&chfdeh=0&chdet=1277250403570&chddm=98141&chls=IntervalBasedLine&q=NYSE:JNK&ntsp=0

http://www.google.com/finance?chdnp=1&chdd=1&chds=1&chdv=1&chvs=Logarithmic&chdeh=0&chfdeh=0&chdet=1277250572116&chddm=1955&chls=IntervalBasedLine&q=NYSE:JNK&ntsp=0

AC

bmbull said...

JNK looks like it pays a dividend monthly -- could be adjusted vs. non-adjusted prices?

Quick Takes Pro said...

bmb,
If they are adjusting actual traded prices then they are criminal. Fine of you are doing some sort of study but the price is the price is the price.

Quick Takes Pro said...

Amit,
There is no excuse for a charting system giving you different values for a simple moving average in the age of computers. Previously, they used to do a lazy calculation rather than recalculating from fresh data in a moving window (hence the name). The lazy way keeps data around forever and is very span dependent.

You get what you pay for with all free online services.

bmbull said...

Well, all may not agree with the practice, but according to StockCharts.com, their "Historical Price Data is Adjusted for Splits, Dividends and Distributions"

Yahoo's historical data is adjusted as well.