Billionaires bankrolled high-profile independents including Canberra's Anthony Pesec ahead of the May federal election, new electoral disclosures show.
But most donors remain invisible, because of the high disclosure threshold.
Independents received around $4.7 million in donations from more than 5500 donors, election disclosure returns published by the Australian Electoral Commission on Monday reveal. Details of donations to parties won't be released until February.
Canberra independent Anthony Pesec received $87,291 from 39 donors, through his Senate group with Gary Kent.
Around $20,000 of that came from Alex Turnbull, son of former prime minister Malcolm Turnbull.
The other $50,000 came from the Climate 200 group. The environmental group also gave Julia Banks $40,000, Kerryn Phelps $47,500, Helen Haines $35,000, Rob Oakeshott's $37,000, and a whopping $145,000 to Oliver Yates.
Electoral returns show Climate 200 was bankrolled by tech billionaire Mike Cannon Brookes and Melbourne University Climate and Energy College adviser Simon Holmes à Court. Cannon Brookes gave $50,000 while Holmes à Court donated $25,000.
The company Climate Outcomes Foundation also donated $195,000 to Climate 200. Company records show Climate Outcomes Foundation is run by Mitchell Hopwood.
But the vast bulk of donors to candidates ahead of the election will never be known.
While individuals and organisations who donate more than $13,800 must disclose their names and addresses to the electoral commissions, smaller donations can be given anonymously.
Although 1378 donations were made to the Steggell campaign, only 13 donations had names attached. This includes two $10,000 donations from William Manos, $57,725 from Anna Josephson over three donations, and $104,000 from wealthy philanthropist siblings Robert and Sandra Purves over three installments.
All up, only $350,726 of the $1.1 million in donations the Steggell campaign pulled in is accounted for under current electoral laws - about a third.
But it's a trend that holds true for other high-rolling independents.
Helen Haines received $421,011 in donations from 1002 donors - but we only know who donated $176,120 of that.
Rob Oakeshott pulled in $105,000 from 350 donors, but we only know where $37,000 came from.
NSW independent Kevin Mack received $155,035 from 55 donors - none of whom cleared the reporting threshold.
UNSW researcher Lindy Edwards said the figures aligned with her research on invisible donations to major parties.
"My work tends to find about 50 to 70 per cent of funding sources for the major parties are undisclosed," she said.
"There can be good reasons for that. The best reasons are if its being funded by lots and lots of people, for very small amounts, Just as likely though it's the combination of very high disclosure thresholds and the weakness of the definition of gifts which means lots of money can be hidden in other receipts."
But Grattan Institute researcher Kate Griffiths said unlike major parties, independents were required to aggregate their donations.
That meant while a big donor could give lots of smaller amounts to a major party to skirt around the cap, an independent candidate would be forced to disclose those same donations.
"This is a loophole that needs to be closed," Ms Griffiths said.
What it meant though was campaigns like Zali Steggall's were truly grassroots.
"Someone like Zali Steggall, who received more than $1 million from 1400 donors, the average donation is about $800. For Oliver Yates, the average donation is $1390, so a bit larger," Ms Griffiths said.
The donations to independents were also small beer compared to those given to major parties, Ms Griffiths said.
Parties reported receiving $94 million from known private sources at the 2016 election and spent a collective $368 million.
But the donations threshold was still well above that of states and territories, and out of line with international practice, both Ms Griffiths and Dr Edwards said.
"We believe a $5000 is more appropriate. As you can see from the data, $5000 wouldn't pick up the average donor by any means," Ms Griffiths said.
Centre for Public integrity director and former counsel assisting ICAC Geoffrey Watson said a limit of $1000 or $2000 could even be appropriate.
"It's got to be a sum which allows voters to participate in the process but it can't be so large that in any sense the politician feels a sense of obligation to the donor," Mr Watson said.
"The current federal disclosure limits are ridiculous, It's much too high. It's very obviously with a disclosure level that high it can be easily manipulated."
The data also reinforces need for caps on campaign spending, Mr Watson said.
Independents spent a total of $6.64 million on the campaign trail.
The Pesec campaign spent around $200,000 on its bid to oust sitting Liberal senator Zed Seselja.
Independent candidate for Bean Jamie Christie also spent more than $145,000 on his campaign. Dr Christie did not receive any donations to his campaign, electoral returns show. He was the most successful independent candidate running for the House of Representatives in the ACT's history.
"The purpose of caps is obviously to stop the deepest pockets having the loudest voice," Mr Watson said.
Mr Watson said he hoped the reforms introduced by Queensland last week would become a "template" for the rest of Australia. The state is set to impose a $6000 cap on donations to candidates and $4000 to parties, while parties will only be able to spend up to $92,000 per endorsed candidate for every electorate contested.