• Available languages: English, Chinese (China, Taiwan), German, Italian
• Compatibility with operating systems: Windows, Linux, Mac (OS X), Solaris
• Type of License: GNU General Public License version 2.0 (GPLv2)
• Author description: JStock makes it easy to track your stock investment. It provides well organized stock market information, to help you decide your best investment strategy.
• Your opinion: It's free, simple and one of the most market-encompassing stock market software I ever used.
• A link to the author website: http://jstock.sourceforge.net/
• A link to the download page: http://jstock.sourceforge.net/download.html

And more importantly it seems LiberKey still doesn't have any stock market app. So I guess this would be a great option!