The DUP has been fined for lodging an inaccurate spending return with electoral authorities.
The Electoral Commission handed a £4,000 fine to the party for errors detailing its expenditure in the 2016 Assembly election.
The DUP return included payments to the value of £49,183.86 that should not have been attributed as party spend, rather individual candidate expenditure.
However, the Electoral Commission found the same payments had also been reported by the candidates as required.
The Commission said it is satisfied the inclusion on the party's return was a duplication.
The return was also missing two payments, valued at £397.50, which the Commission said should have been reported.
A spokesman for the Electoral Commission said the DUP had paid the £4,000 fine.
"The party has informed the Commission that it has reviewed its procedures to prevent a recurrence of these errors," he added.
A DUP spokesman said: "The Electoral Commission has made clear that this was a case of 'duplication'.
"The expenditure in question was mistakenly declared twice - once in the party's central campaign return and then again in the candidates' individual spending returns.
"This error was corrected in an amended campaign expenditure return.
"We regret that these administrative errors led to our election spend being recorded as higher than should have been the case.
"The party has put in place new processes to guard against this in future.
"The fine has been paid in full. The Commission has confirmed this matter is now closed."