I have the free version of Stock + - it works well enough for my needs. It displays the ticker in the Menu Bar. If you literally meant on the Desktop, with text as large as the ticker in your example, this won't do it.
I have not tested this myself... but it should work. There is an app called Geektool that can be used to display different things on the desktop. You use "Geeklets" to display what you want. This web site has a bunch of Geeklets and if your search for "stocks" I see some listings there.
There is a forum thread here that shows some of the things Geektool can do.