# Difference between google finance and yahoo finance?

I am wondering about the huge differences of the data provider google finance and yahoo finance. I am interested in the monthly data from adidas listed on xetra. In google: ETR:ADS and in yahoo finance: ADS.DE - Xetra.

There is a huge difference in the data, e.g. consider the 02.06.2008:

Date             Open    High   Low     Close   Volume
Jun 2, 2008     45.49   45.60   44.93   45.05   1,037,644


yahoo finance (german):

Datum   Eröffnungskurs  Max.    Tief    Schluss Ø Volumen   Adj. Schluss*
2. Jun 2008 45,49   46,48   39,39   40,11   1.603.100   38,34


As you can see the open ("Eröffnungskurs") is the same. But all other values are different. So currency seems not to be the problem. But why are these values so different?

Also, why is there a yahoo finance gap in August 2008? I don't get the value of the 01.08.2008 but the 18. Aug 2008 instead? Since I am using the yahoo finance data I have to fill in this gap, what value / what method would be appropriate?

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I rather work on a multivariate brownian motion problem than answer this. Such kind of data cleansing or data filling is a nasty and very time consuming issue. I would have suggested checking your dates (as you use a German version for yahoo and maybe you ended up requesting 6/2, 2008 vs 2/6/2008 data) but then the opening price is identical. Good luck! In general keep in mind this is not Bloomberg, and you always get what you....... –  Matt Wolf Jun 20 '13 at 17:01
I did not end up requesting the wrong date, you can check it. –  Ivanov Jun 20 '13 at 17:19
Related question: quant.stackexchange.com/q/942/1587 –  Darren Cook Jun 27 '13 at 6:16

The difference is usually explained by

• the way the end-providers (Google, Yahoo) aggregate the data they get from their vendors
• getting prices from same exchange, but from different trading platforms
• missing corporate actions or dividends and many more.

If you have a discrepancy in a price usually it's a good practice to check Investor Relations section on company's website. For example, for Adidas you'd see that the correct value for 6/2/2008 is 45.05.

The ultimate source, of course, would be checking the exchange for that price. If exchange allows to get the price that far back one should use that value. Frankfurt Stock Exchange in this case allows you to get this period. Note that there are two tabs: Xetra and Frankfurt, they simply represent two different trading platforms.

Yahoo, btw, is getting stock data from Hemscott (which was acquired by Mornignstar.) Hemscott is not the most accurate source of EOD stocks.

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