Today I was confronted with Eigengeschäfte and found "business for own account or "trade for own account" in a number of the common online dictionaries. That didn't really sound convincing so I used Wikipedia to sort it out.

Google found this page http://de.wikipedia.org/wiki/Eigenhandel

and lo and behold, there is a nice blue underlined "english" link at the side to take us here http://en.wikipedia.org/wiki/Proprietary_trading

The content of these two articles matches, so schwuppdiwupp I've got a decent translation "proprietary trading".

And that is the Wonder of Wikipedia. Don't you just love it!