I need a way from within client-side Javascript to find a full company name given a ticker symbol. I am aware of Yahoo Finance's interface at:
http://finance.yahoo.com/d/quotes.csv?s=TKR&f=n
and am able to access that via YQL (since this is cross-domain). However, that doesn't return the full company name, yet Yahoo Finance has such because it appears in their charts for the company and on their pages about the company.
I don't need for the solution to be via Yahoo Finance... just mention it here as I already know about it (and am accessing it for other data).
One of the community-provided YQL tables looks like it will work for you: yahoo.finance.stocks.
Example YQL query:
select CompanyName from yahoo.finance.stocks where symbol="TKR"
Update 2012-02-10: As firebush points out in the comments, this YQL community table (yahoo.finance.stocks) doesn't seem to be working correctly any more, probably because the HTML page structures on finance.yahoo.com have changed. This is a good example of the downside of any YQL tables that rely on HTML scraping rather than a true API. (Which for Yahoo Finance doesn't exist, unfortunately.)
It looks like the community table for Google Finance is still working, so this may be an alternative to try: select * from google.igoogle.stock where stock='TRK';