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Hquote is a piece of software that downloads data from
Yahoo. It may not be suitable for
all purposes.
Here's a list of the problems I've found with Yahoo's
data.
1. No delisted history - any system testing you do
based on Yahoo data is subject to population bias. ie you can only test on
the stocks that are currently listed.
2. Significant
inaccuracies for any stock exchange that trades in increments less than
1c. This includes the Australian Stock Exchange (ASX), Singapore Exchange,
some NASDAQ stocks and most OTCBB & Pink Sheet stocks. This happens
because Yahoo's data is rounded to the nearest cent. For example, there
are 14000 listed instruments on the ASX. Over 8000 of them are currently
trading below 20c which means they move in either 0.5 or 0.1c increments.
Since Yahoo only prices in cents this introduce VERY SIGNIFICANT
innacuracies. - eg. a 2.6c shown as 3c represents a 15% error).
3. Normal dividends
are adjusted by subtracting all historical data by the dividend amount.
Exchanges such as the ASX do not adjust price data for standard dividends.
By diluting it the way they do, any technical analysis or backtesting no longer
shows a correct % return, nor does it show a critical technical levels such as
support and resistance.
4. No
sector information - critical if you want to perform sector-based analysis. There are multiple classifications systems in
use (GICS & DJ) - you need to ensure that your data aligns with your
classification systems so you can easily compare a sector index to the right
stocks.
5. Significant
number of missing stock splits and other capital adjustments.
6. There is no
guarantee that Yahoo will continue to supply data, especially to automated
download programs. In Yahoo's Terms of Service, they have a clause which
says "You agree not to reproduce, duplicate, copy, sell, trade, resell or
exploit for any commercial purposes, any portion of the Service (including your
Yahoo! I.D.), use of the Service, or access to the Service.". Companies
that produce Yahoo downloaders are effectively exploiting the Yahoo service and
are therefore in breach of the Yahoo Terms of Service. Therefore, Yahoo may shut down these
types of automated downloading programs very easily.
So, whilst the
Yahoo data is free to obtain from the Yahoo site, you need to determine what you
really need from the data. If you're ever likely to want to view accurate historical charts (eg for system
development / backtesting / historical interest) then the old adage "you get
what you pay for" certainly applies here.
In the
case of programs that extract data from Yahoo, the exchange sends data to
Reuters. Reuters interpret the data, put it into their databases, then
take an extract of the data and send it to Yahoo. Yahoo interprets the
data, puts it into their database, then extracts it onto the Yahoo Finance web
site. Then the downloading program obtains data from the Yahoo site,
interprets it, and puts it onto the user's PC. If at any step of the above
process, the interpretation is slightly incorrect then you have a discrepancy
between actual events on the market and data you receive. This is
clearly the case with the HQuotes.
Best regards,
Richard
Dale.
Norgate Investor Services
- Premium quality Stock, Futures and
Foreign Exchange Data for
markets in Australia, Asia, Canada, Europe,
UK & USA -
HQuote works great. pay your entry fee and get it. Best
deal in town.
I have used it for 2-3 years. Just don't try downloading data
on 3000
stocks.. as it will take forever, just as any other downloading
service will into Metastock. Try no more that 200 at a time. I have
cable modem and that takes a few minutes. You can also download
mutual
fund data.
Best of luck - and pls go back and look at old e-mails on the
subject. This subject comes up every 2
weeks...
Rvalue1
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