Character as a business fundamental
I don't separate core business values from core personal values. That concept seems odd to me, actually. I would not want to be associated with a business that did not operate according to a generally acknowledged set of noble principles. That's not to say that my personal governance system must be totally congruent with those of my colleagues. We all just have to be acceptably consistent within the ethical and behavioral boundaries implied by the broad principles.
My own core values derive from life-long wrestling with what I have managed to learn from parents, philosophers, prophets, poets, and personal experience - the Five P's of character-building, if you will. But they still are not clear enough to be set down as firm guidelines. It's difficult simply to state them.
For me, values must be extracted from and applied within specific contexts. If a single statement were to apply, it might be, "Look carefully and gratefully at the world, then do the right thing, as best you can discern it. Accept the outcomes. Then re-examine the world, carefully and gratefully, and do the next right thing."