My submission for your review.
I've read the brief and do understand you need for a an Oak Tree, however please keep an open mind...A tree is good and is industry and company name relevant? A tree as a stand alone icon (without text) truly say Oak Capital Investment or does having a having a customized letter O that is Oak Capital,
The ring of oak leaves represents "Focus" in terms of 100% dedication to your clients and their investments
Scott.