Kushner, the president's son-in-law and a top White House advisor with a sprawling portfolio, is just one of many in Trump's circle whom Mueller is investigating in his ongoing probe into Russian meddling in the 2016 election.
USA TODAY previously reported that the FBI was investigating Kushner for his contact with Russian officials, but there was no word at that time that his financial dealings were part of the probe.
The news comes as the Justice Department continues its investigation into Russian meddling in the 2016 election and the Trump administration's potential ties to Russia. The inquiry has expanded to include an examination of whether Trump attempted to obstruct justice, The Post reported Wednesday.
FBI agents and federal prosecutors have also been examining the financial dealings of other Trump associates, including former national security adviser Michael Flynn, former campaign chairman Paul Manafort and Carter Page, who was listed as a foreign policy adviser for the campaign. He is reportedly interviewing three top intelligence officials - Director of National Intelligence Dan Coats, National Security Agency Director Mike Rogers and retired deputy NSA director Richard Ledgett - as part of the probe as early as this week.
"Current and former leaders in the intelligence community have repeatedly said there's been no effort to impede the investigation in any way,"Ronna Romney McDaniel, chairwoman of the Republican National Committee, said in a statement".
Mueller's plans emerged just a week after former FBI Director James Comey told the Senate Intelligence Committee that Trump pressed him in February to ease up on an investigation into Flynn.
Comey also said Trump repeatedly sought assurances that he wasn't a target of the Russian Federation investigation.
"Regardless of recommendation, I was going to fire Comey knowing there was no good time to do it", Trump told Lester Holt of NBC News in an interview broadcast May 11. "It would be standard practice for the Special Counsel to examine financial records to look for anything related to Russian Federation".
"When I made a decision to just do it, I said to myself - I said, you know, this Russian Federation thing with Trump and Russian Federation is a made-up story", Trump told Lester Holt of NBC News in an interview broadcast May 11.
Comey told senators on June 8 that Trump's shifting explanations for dismissing him were "lies, plain and simple".
Before he met with the president, Comey gathered his leadership team at the Federal Bureau of Investigation to discuss with them whether he should be prepared to assure then-President-elect Trump that the Federal Bureau of Investigation was not investigating him personally.
"While the president has the right to, he has no intention to do so", Trump spokeswoman Sarah Sanders told reporters. Coats later told lawmakers he never felt pressured to intervene.
On Thursday, Kushner's lawyer said any such scrutiny of Kushner's business would be "standard practice".