"In addition to contributions and grants… speeches by President, Secretary, and Chelsea Clinton have helped support the implementation of the Clinton Foundation's work around the world," the statement published on the organization's website on Thursday said.
The exact sum of money received by the foundation could be anywhere between $11.2 million and $26.4 million because the report calculated speech fees using payment categories such as "from $500,001 to $1,000,000."
According to the Washington Post, Clinton Foundation officials said that the payments were not previously disclosed because the organization views them as "revenue" rather than donations.
Clinton announced on April 12 that she would step down from the board of the Clinton Foundation and run for the US presidency. Since then, the charitable organization has faced criticism over accepting donations from foreign governments, a practice that could be seen as a conflict of interests in light of a presidential bid.
Hillary Clinton and her team are often accused of a lack of transparency. In March, the New York Times reported that Clinton used a personal email address for working purposes while serving as Secretary of State. Earlier this week, The Wall Street Journal reported that her staff blocked the release of some politically sensitive documents requested under the Freedom of Information Act.
In mid-May, a poll conducted by conservative Fox News revealed that some 44 percent of US registered voters see Hillary Clinton as less ethical than other potential 2016 presidential candidates.
