Parties spent less than half what they spent on previous Stormont election
Parties in Northern Ireland's last Stormont election spent less than half what they spent on the previous election, the Electoral Commission said.
The nine groupings ran up bills worth a total of £150,080 on campaigning for March's poll.
That compared to £343,558 just 10 months earlier.
The most recent poll was called following the resignation of the late Martin McGuinness as deputy first minister in January in protest at the DUP's handling of the Renewable Heat Incentive scandal.
Ann Watt, Head of the Electoral Commission in Northern Ireland, said: "We are disappointed that more than a third of the parties submitted their spending returns late or not at all.
"These failures are now being considered in line with the Electoral Commission's enforcement policy."
Four smaller parties submitted nil returns, meaning they submitted the forms but did not spend any money.
Sinn Fein spent the most at £46,591 while the Alliance Party was second placed with £32,456 and the Ulster Unionists spent £26,443.
The Democratic Unionists spent £21,929.