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Hi Jim,
HQuote is a Yahoo downloader. I've previously put
together a list of the problems associated with these types of
programs:
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 inaccuracies. - 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. Also, there are multiple
classifications systems in use (US - both 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 and Yahoo may shut down these types of
automated Yahoo downloading programs very easily.
The best analogy I can use for data
feeds is they are like a game of Chinese Whispers. http://www.chinesewhispers.com/chinesewhispers.php
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.
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. Caveat
emptor.
Best regards,
Richard
Dale.
Norgate Investor Services
- Premium quality Stock, Futures and
Foreign Exchange Data for
markets in Australia, Asia, Canada, Europe,
UK & USA -
I need a new data feed..my tc2k gave me problems and i have
stopped
using that source..I saw Hquote on www...they certainly are
reasonably priced,and a feed for tradestation as well..is anybody
using
this...comments good or bad would be appreciated...an can
anyone give me any
other good data source comments for
Metastock...thanks.....
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