According to the publication's review of public disclosures, more than $26 million was donated to the Clinton Foundation by at least 60 companies when Clinton held public office in 2009-2013.
As Democratic and Republican hopefuls line up for the upcoming presidential campaign, increased media scrutiny is commonly becoming the unofficial vetting process of potential candidates.
"The Clinton Foundation has raised hundreds of millions that it claims is for charitable causes, but clearly overlaps with Hillary Clinton's political ambitions," conservative political action group director, Tim Miller, told the newspaper.
The Clinton Foundation itself rebuked critics in Thursday's statement addressing the latest suggestions of foul play.
"Should Secretary Clinton decide to run for office, we will continue to ensure the Foundation's policies and practices regarding support from international partners are appropriate, just as we did when she served as Secretary of State," the statement read.
A former Republican employee described these contributions to the newspaper as a "bonanza for opposition researchers."
"They enable her critics to suggest the appearance of a conflict of interest," Jack Pitney, now a professor of politics at Claremont McKenna College, was quoted as saying.
Established in 2001, the Bill, Hillary and Chelsea Clinton Foundation works broadly in areas of health security, economic empowerment, leadership development, citizen services, as well as racial, ethnic and religious reconciliation.
In the 2008 presidential campaign, Hillary Rodham Clinton was edged out in the primaries by eventual Democratic Party nominee and current two-term US President Barack Obama.
