Aides to former President Bill Clinton helped start a Canadian charity that effectively shielded the identities of donors who gave more than $33 million that went to his foundation, despite a pledge of transparency when Hillary Rodham Clinton became secretary of state.

The nonprofit, the Clinton Giustra Enterprise Partnership (Canada), operates in parallel to a Clinton Foundation project called the Clinton Giustra Enterprise Partnership, which is expressly named in an agreement Hillary Clinton signed to make all donors public while she led the State Department. However, the foundation maintains that the Canadian partnership is not bound by that agreement and that under Canadian law it cannot make contributors to it public.

The foundation cited that restriction last weekend in explaining why it did not disclose $2.35 million in donations from the chairman of Uranium One, the subject of an article in The New York Times last week. The article examined how company executives and shareholders had sold a majority stake in the company — and with it a significant portion of American uranium reserves — to an arm of the Russian government in a deal that required the approval of the U.S. government.

"This is hardly an effort on our part to avoid transparency," said Maura Pally, acting chief executive of the Clinton Foundation.

Instead, the foundation said that the partnership was created by Canadian mining financier Frank Giustra to allow Canadian donors to get a tax benefit for supporting his work with Bill Clinton — a benefit that came with the price of respecting Canada’s privacy laws. On Wednesday, the partnership issued a statement citing a legal opinion that "charitable donors have an expectation and right of privacy."

However, interviews with tax lawyers and officials in Canada cast doubt on assertions that the partnership was necessary to confer a tax benefit; an examination shows that for many donors it was not needed, and in any event, since 2010, Canadians could have donated to the foundation directly and received the same tax break. Also, it is not at all clear that privacy laws prohibit the partnership from disclosing its donors, the tax lawyers and officials in Canada said.

The partnership, established in 2007, effectively shielded the identities of its donors — and the amount they gave — by allowing them to bundle their money together in the offshoot Canadian partnership before it was passed along to Clinton Foundation programs. The foundation, in turn, names only the partnership as the source of those funds.

In response to questions about the tax-break rationale for the formation of the offshoot charity, the Canadian tax experts pointed out that donations to the partnership from other charities and foundations would not have been eligible for tax breaks. That is because the donors who gave money to those other charities had already received their tax benefit. Records show that those nonprofit groups accounted for about half of the donations to the Canadian partnership.

For example, the Uranium One chairman, Ian Telfer, used his family charity, the Fernwood Foundation, to make his donations to the partnership. Telfer would have received a tax benefit when he first put his money into Fernwood, not when Fernwood donated to the partnership.

"There would only be one tax benefit no matter how many charities it passes through," said Mark Blumberg, a tax lawyer in Toronto.

The partnership might have been necessary to provide a tax benefit to early individual donors, but not since 2010. That year, the Clinton Foundation was specially designated by the Canadian government, allowing Canadians to write off donations given directly to it.

"It makes no tax difference," Blumberg said, "whether a donor gives the money to a Canadian charity or the Clinton Foundation."

Because of long-standing concerns about potential conflicts of interest, the Clinton Foundation agreed to strict limits on foreign government donations while Hillary Clinton served as secretary of state. The existence of the Canadian Clinton Giustra partnership has implications for the foundation’s recent pledge to limit donations from other countries, and disclose all donations quarterly, while Hillary Clinton is running for president. Pally said the foundation "will only accept funding from a handful of governments, many of whom the foundation receives multiyear grants from, to continue the work they have long partnered on."

But the statement did not make clear whether parallel organizations like the Canadian entity would be allowed to accept donations from governments that the foundation itself would not take. The Canadian partnership’s records show that it took donations from outside Canada in 2009 and 2010, the origins of which do not have to be made public. Foundation officials said it was their understanding that the non-Canadian donations to the partnership had not come from governments.

How many more such entities exist, or might be created in the future, is also unclear. A search of charity registrations in Britain, for instance, found a William J. Clinton Foundation UK that has raised about $1.5 million for a climate change initiative. Foundation officials said those donations were made public.

Canadian records show that the partnership was incorporated in August 2007, but it was not until Dec. 5 of that year that it was registered to accept charitable donations. The founding board included Bruce R. Lindsey, a longtime aide to Bill Clinton who at the time served as chief executive officer of the Clinton Foundation, and Eric Nonacs, another aide to Bill Clinton and Giustra.

Six days earlier, in response to questions from The Times, the foundation turned over records that by law must be made public and that made clear that the Clinton Foundation had attracted a $31.3 million donor. The records contradicted the foundation’s repeated assertions that a $31.3 million line item on its tax return was an aggregate of small contributions. It initially refused to identify the donor. But with the foundation’s activities drawing scrutiny amid Hillary Clinton’s first run for president, the foundation reversed course and Giustra stepped forward as the donor on Dec. 18.

The following month, The Times reported that the $31.3 million donation came after Bill Clinton accompanied Giustra to a dinner with the president of Kazakhstan; days after that dinner Giustra finalized a lucrative uranium mining deal in the Central Asian republic.

This week, in an interview with Bloomberg News, Giustra said he was frustrated with the media treatment he had received, and echoed the foundation’s position on Canadian privacy law, saying that by law he could not even tell the Clinton Foundation who his donors were.

"We’re not trying to hide anything," he said, adding that all the money, "every penny," was passed onto the Clinton Foundation to fund specific charitable initiatives.

But tax specialists said the disclosure prohibition was not as clear-cut as the foundation made it seem.

A spokeswoman for the Canadian Revenue Agency, Magali Deussing, said that the tax law "does not regulate whether a registered charity or other qualified donee can disclose donor information." However, other federal or provincial privacy laws may apply, she said.

Malcolm Burrows, the head of philanthropic advisory services at Scotiabank in Toronto, said that "general Canadian privacy rules" could apply to charities, but that "in most cases" it is not a concern because charities and their donors want the publicity.

"The irony here is that the foundation is saying they’re not allowed to do it," he said. "But many foundations want to put that information out there."

Blumberg, the tax lawyer, said that while privacy laws would prohibit charities from misusing donor information for commercial purposes, they generally did not otherwise prevent disclosure of donors. But, he said, laws in the province of British Columbia — where the Clinton Giustra partnership is set up — are stricter. But even there, he said, a charity could arrange for disclosure of donors if it wanted to, something Giustra is now saying he will attempt to do.

"If an organization operating in British Columbia wants to be transparent about who their donors are, then they could easily provide an opportunity for donors to consent to the disclosure of their name and/or donation amount," Blumberg said.

In disclosing its contributors, the Clinton Foundation says only that the Canadian partnership gave more than $25 million — making it among the foundation’s biggest donors. Canadian tax records show that the partnership took in $33.3 million between 2008 and 2013.

About half the $33.3 million was given by other charities, which, like the partnership, must file financial reports with the Canadian Revenue Agency. The reports list donations made by the charities — but not donations received — making it possible in some instances to identify donors to the partnership. Searching the records in this way found that in addition to the $2.35 million from Telfer’s foundation, a charity controlled by Giustra, the Radcliffe Foundation, gave $10.5 million to the partnership that bears his name.

That leaves about $20 million from donors whose identities remain a mystery, at least for now.

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