[R-SIG-Finance] yahoo historical data quality

James Toll james at jtoll.com
Fri Apr 10 20:32:14 CEST 2009

Andy et al.,

I have a question that's really an extension/amalgam of your question  
regarding the quality of Yahoo historical data with regard to the  
market capitalization data you were inquiring about last week  
(Specifically, I'm interested in outstanding and floated shares).   
Given that it's free data, one can't be overly critical, but have you  
found Yahoo's market cap data to be both accurate and timely?  I don't  
have a reference to compare the data to, so I'm unsure.



On Apr 10, 2009, at 10:10 AM, Andy Zhu wrote:

> Hi,
> Encountered problem with historical price, missing data from yahoo/ 
> finance. Here is an example: ticker = 'ATML', dates =  
> c('2000-08-28', '2000-08-29') (Mon and Tue). Yahoo doesn't show data  
> for these two dates so Quantmod simply doesn't pick them up with  
> Yahoo. However, when I check with Google/finance, it does show up  
> data for these 2 dates. How do you guys handle these missing data in  
> a systematical way? do you have any information of how to  
> communicate with Yahoo person?
> Thanks.

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