Practically the only tax the Assembly currently controls which could be used to raise more revenue is the Regional Rate.
That raised about £640m in 2019/20, or about 5% of the total recurrent and capital spend across the Northern Ireland departments.
The case for greater fiscal powers includes the use of tax changes (cuts) to promote certain economic sectors and the possibility that linking decisions about spending to ones about taxing would improve accountability and the quality of decision-making.
There are risks too - the tax policy of a regional assembly might show undue preference to local vested interests, though it is not unheard of for national governments to fall into such a trap.
Tax cutting agendas will tend to be most popular with politicians and their electors, but of course what we are currently thinking about is the possibility of revenue increases.
The options may be wider than first impressions suggest.
Westminster can legislate to give the Executive more tax powers. It already has with respect to long haul air passenger duty and corporation tax, although significantly these concerned an actual and prospective tax reduction.
The Assembly does have competence to introduce "new taxes" - those which do not exist in GB.
The really big ticket item would be domestic water charges. It is worth remembering that farms and businesses have long paid such charges.
There would be two benefits from these. First, the revenues which were raised directly and, second, NI Water would acquire the power to borrow to meet further resource needs.
It is likely that NI funding would benefit to the tune of £200m. In 2018/19 the subsidy to cover the absence of charges was £278m.
Political decisions would have to be made about the rate at which households were charged and the extent of exemptions on the grounds of low income as a method of equality-proofing this policy.
There follows a reasonably long list of measures each of which could raise a smaller amount - perhaps several tens of millions - but in combination could be significant:
For sure, these are not easy choices but real politics is about priority setting and trade-offs. There is a sense of déjà vu.
The historian Patrick Buckland records how at the foundation of the state of Northern Ireland a team of officials had to go to the Treasury in London to try to negotiate a more generous financial deal.
With hindsight it would have been better if Stormont had been given wider fiscal powers - that would have been true back in 1921 and again at the time of the 1998 Agreement.
In 2009 the head of the ERINI think-tank Victor Hewitt tried to persuade the Assembly to assume greater fiscal self-responsibility and got a very dusty response. Perhaps this time will be different.
Dr Esmond Birnie is an economist at Ulster University