The Opportunities Party's failed campaign to get into Parliament cost founder Gareth Morgan at least $1.7 million out of his own pocket.
The party declared another $300,000 donation from Morgan last week, on top of previous donations totalling $1.4 million.
Morgan's party, which was formed just 10 months before the election, won 2.2 per cent of the vote in preliminary results and no electorate seats.
On top of the donations, Morgan also promised to spend up to $1 million giving to charities as part of a stunt which he hoped would attract more voters.
As a relatively new party with no established backers, TOP received only $41,000 from the Electoral Commission for its broadcasting allocation - compared to more than $1 million for National and Labour.
Morgan, an economist and philanthropist, made his fortune in economic forecasting, investment and banking. While his net worth is not known, he famously made $47 million from his $75,000 stake in his son Sam's company TradeMe when it sold to Fairfax.
He has previously said that TOP is a long-term project and that it will stand again in 2020.
Other parties also received some large donations in the lead-up to the September 23 election.
The National Party received a series of donations totalling $51,720 from Philip Hong, a businessman whose interests include renting out commercial property.
It declared $57,615 from hotel owner Lani Hagaman. Hagaman and her late husband Earl were regular donors to National and Act, and were recently involved in a defamation case against former Labour leader Andrew Little.
National also received $57,400 from Heartland Bank and $50,000 from investment firm Lane Capital Group.
The Labour Party declared a $65,000 donation from Tom Pan, and $100,000 from the Dairy Workers' Union.