The inner workings of a mysterious off-the-books arm of the Clinton Foundation were partially revealed in the hacked emails of Hillary Clinton campaign chairman John Podesta.

The little-known Haiti Development Fund, an LLC incorporated in Delaware in August 2010, was created by the Clinton Foundation with an initial endowment of $20 million from shady Canadian mining mogul Frank Giustra and Mexican billionaire Carlos Slim.

The Fund was supposed to supply desperately needed seed money to Haitian entrepreneurs after an earthquake devastated the country in January 2010.

But The Post found only one project that it funded with a fraction of the start-up cash.

Since the Fund is incorporated as a private entity and not a non-profit, it is not subject to the same disclosure rules as a public charity.

And the Clinton Foundation never disclosed the Fund as a “related entity” on its tax filings as required by IRS rules. It was only after the Clinton Foundation, under mounting scrutiny and media pressure, “voluntarily” decided to refile five years’ worth of tax returns in 2015 that the Fund appears on the forms.

The for-profit Fund was managed by Jean Marc Villain, who was going through a bankruptcy in 2010 when he was working for the Clinton Foundation. The non-profit paid him an annual salary of $100,000 to oversee the Fund, according to pay records attached to the Podesta emails.

The Florida Elections Commission found that Villain also had violated state laws in 2001 when he did not file donation reports for the Haitian-American Political Caucus, a political committee where he was listed as treasurer.

“This cries out for an audit or an investigation,” said Ken Boehm, chairman of the National Legal and Policy Center a Virginia-based watchdog group. “Its director was in bankruptcy and there’s almost nothing in the public record showing what happened to the millions of dollars it supposedly was going to use to help poor Haitians.”

Giustra, one of the biggest donors to the Clinton Foundation, is also no stranger to controversy. In 2005, he and President Clinton traveled together to Kazakhstan to meet with the former Soviet republic’s authoritarian leader. Days after that meeting, Giustra acquired uranium assets in three of the country’s state-run mines — a venture valued at more than $3 billion. Both Giustra and Clinton have denied that the former US president helped him cement the Kazakh deal.

At least some of the Haiti Fund cash ended up with Haitian entrepreneurs. According to a Clinton Foundation press release, the Fund made its first investment of $415,000 in a group of artisans in the Caribbean country, in August 2011. That year, the Clinton Foundation’s tax filings show $307,000 going to the Fund.

But in that same year Villain had bigger projects in mind requiring more than $12 million, the emails show. In November 2011, he requested a meeting with Podesta, who was filling in as head of the Clinton Foundation.

“I planned to send notice to the [Investment] Committee to schedule a meeting to consider taking action on a pending transaction and the presentation of 8 investment opportunities … totalling $12.3 million with a potential of 2,775 prospective new jobs,” writes Villain in an email to Podesta’s secretary.

In a return email, Podesta said he would get Villain an answer the next day.

But it’s not clear from Clinton Foundation tax filings if the cash ever made it to Villain’s projects, or what those projects were.

Villain left the Clinton Foundation in 2013 and now works for a hospital in South Carolina, according to his LinkedIn page. He could not be reached for comment.

The Clinton Foundation did not return repeated requests for comment.