Analysis by Danske Bank suggests “political uncertainty” has contributed to consumer confidence in Northern Ireland hitting a four-year low.
It said confidence was also dented by inflation squeezing household spending.
The bank monitors consumer sentiment in surveys of more than 1,000 people every four months.
Chief economist Conor Lambe said more than a third of respondents felt the lack of an executive was impacting negatively on confidence.
Consumers surveyed in December were also more downbeat about their finances due to inflation – then around 3%.
Mr Lambe added: “With consumers facing significantly higher prices at the checkouts, it is not hard to explain why there was such a large fall in sentiment around current household finances.”
Inflation is forecast to ease slightly this year.
But the bank said it still expected “household spending power is to remain under pressure.”