Checking Discrepancies Between Displayed and Downloaded Price Data

Summary

The document reports a discrepancy between a historical price table displayed on a financial website and a CSV download for the same instrument and date range. The questioner observes that the downloaded values appear to diverge from the on-page data partway through the period, and asks whether a setting related to corporate actions or another cause might explain the difference. The issue is framed as a data-quality problem rather than a trading strategy or analysis method.

The accepted response does not identify the cause or verify the reported discrepancy. It recommends comparing the values with another source, noting that an alternate finance service showed data consistent with the website’s displayed table, and suggests reporting the possible glitch to the original provider. This provides a basic validation practice: when two delivery formats from one source disagree, cross-check the series against an independent source before relying on it. The evidence is anecdotal and limited to the example described, so it does not establish how common such mismatches are or what caused them. Corporate-action adjustments and other potential explanations remain unresolved.

Key ideas

• A provider’s displayed history and downloadable file can disagree for the same instrument and dates.
• Cross-check suspicious historical prices against an independent data source.
• The response does not determine the cause of the reported discrepancy.
• The example does not establish how often such download mismatches occur.

Tags

# Downloaded CSV from Yahoo different than the same data when displayed on page?


# Downloaded CSV from Yahoo different than the same data when displayed on page?












Not sure, if this has already been asked or if I'm just overlooking a simple switch (such as for dividends or splits or something), so I'd like to ask for help:

I'm very aware of the fact that there can be occasional errors in historical data downloaded from Yahoo (or any other of the free data providers, for that matter). But I just noticed that the downloaded CSV file contains different data than that very same data, when displayed on screen. As an illustration, please check:

http://finance.yahoo.com/quote/AIR.DE/history?period1=1194994800&period2=1200265200&interval=1d&filter=history&frequency=1d

which displays historical data for the Airbus group (from Nov 14, 2007 to Jan 14, 2008). And then please download the CSV file that supposedly should contain that very same data (the link on top of the page gives this link):

http://chart.finance.yahoo.com/table.csv?s=AIR.DE&a=10&b=14&c=2007&d=0&e=14&f=2008&g=d&ignore=.csv

Note that from Nov 28, 2007, onwards the data in the downloaded CSV seems to be completely wrong. Has anyone else experienced this? Am I doing anything wrong?

Any help would be much appreciated.

## Answer by Jan Sila (score 2, accepted)

https://quant.stackexchange.com/a/29633

That's quite odd, I have no explanation, so I'd suggest look at different source of the data. Bloomberg if you got access to it, or Finance Google. FG shows same data and the CSV looks alright - same data as the online table.

Maybe contact yahoo finance that there's a glitch, I never came across something like that.

Shown in full with attribution under the source's licence. Licence: CC BY-SA 4.0 (Stack Exchange)

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.