Sinn Fein was again by far the richest party, raising £1.1 million and spending £1.2 million during 2015.
However, it is unclear where all the money which the party says it collects from its elected representatives goes.
According to former Sinn Fein MLA Phil Flanagan’s testimony to the High Court earlier this year, the ‘average industrial wage’ which every Sinn Fein politician and employee is paid is £24,000 a year.
If the party’s 29 MLAs, four ministers and seven special advisers had each taken £24,000 and paid the remainder to the party, that would equate to more than £1.3 million – more than the figure which the party has declared as its total income across all categories, including membership fees and its significant fundraising operation in the United States.
The accounts detail just £730,637 in donations.
Earlier this week it emerged that an internal Sinn Fein report has recommended an end to the ‘average industrial wage’ policy, although it is not yet clear whether that will mean raising the £24,000 figure or simply allowing politicians to retain all of their salaries.
The Electoral Commission figures show that last year DUP earned £533,682 and spent £511,766. The UUP netted £412,805 and spent £310,613, while the SDLP received £543,704 and spent £600,851.
Income for the four largest Stormont parties increased by £194,975 and expenditure rose £6,211 compared with 2014.
The money came from official grants, donations and subscriptions.
The commission repeated its recommendation that the Government should extend the same transparency regime on party funding to Northern Ireland as applies elsewhere in the UK as soon as possible.
Details of any large donors have to be sent to the Electoral Commission but are not made public due to security concerns.