For now, we are naming and aligning our portfolios to funding sources. That's how we were advised to do it. Those sometimes match business unit or department names (and the funding comes from their budgets) and align to our organizational taxonomy, but not always. Sometimes funding come from sources that transcend the enterprise. Most of our projects are funded through an enterprise investment funding source (with its own cost center).
I say "for now" because while that's how we were advised to do it by our consultants, I'm not certain that it's right, and I'm not married to the concept in the long term.
