Poorer UK regions such as Northern Ireland would face greater economic uncertainty than richer regions if there is a vote to leave the EU, a think-tank has suggested.
The Sheffield Political Economy Research Institute (SPERI) has analysed the different trade relationships that the UK nations and regions have with the EU.
It concludes that Northern Ireland, the North East and South West appear to be the most dependent on free trade in goods with other EU countries.
It has also looked at how EU economic development funds are distributed across the UK.
On a per-head basis Northern Ireland is the second biggest recipient of those funds, behind Wales.
SPERI says if the UK were to leave the EU, the issue arises of whether the Westminster government would adopt a similar regional development programme.
It asks whether such funds would be "matched in absolute terms" and whether they would have the same priorities.
The report echoes findings by other research organisations (Oxford Economics, NERI) that Northern Ireland would be relatively more vulnerable than other parts of the UK to potentially negative impacts of a withdrawal.
A spokesman for Vote Leave said that as the UK is a net contributor to the EU, leaving will "will free up extra public resources to invest in regions like Northern Ireland not less".
"The threat to the poorest areas of the United Kingdom is remaining a member of the EU," he said.
"If we stay we will be asked to pay more in and get less back."
'Cocktail of risk'
He added that the latest HMRC export figures show Northern Ireland is seeing a decline in exports to the EU and rapid growth to the rest of the world.
A spokesperson for the NI Stronger In campaign said there was "little of surprise" in the report.
"This cocktail of risk highlighted in the Treasury report published earlier this week, and confirmed by the University of Sheffield , places Northern Ireland at the forefront of the predicted economic downturn should vote leave succeed.
"To adopt the Prime Minister's phrase, 'the DIY recession' will hurt most in places like Northern Ireland."
Meanwhile a new poll by Lucid Talk published in The Sun suggests 54% of voters in Northern Ireland will choose to remain in the EU.
The poll, of 1,090 people on a demographically balanced panel, suggested 35% will vote to leave with a further 9% undecided.
The internet poll was carried out last week and has a margin of error of +/- 3%.
The referendum on whether Britain should leave the EU will be held on 23 June.