Ex-chancellor Nadhim Zahawi paid a penalty as part of his tax dispute with HM Revenue & Customs, the BBC has been told.
The Conservative Party chairman is facing claims he tried to avoid tax and had to pay it back.
On Saturday, he said he did make a payment to HMRC to settle the issue.
It was previously reported the money he paid included a penalty, but this had not been confirmed.
On Sunday evening, Mr Zahawi's allies insisted he would continue in his role.
The BBC also understands the tax issue was resolved while Mr Zahawi was chancellor between July and September last year - and the total amount paid is in region of what has been reported, of about £5million.
Pressure has been growing on Mr Zahawi to give more details about his finances after reports emerged last week he had agreed to pay millions of pounds to HMRC to settle his tax affairs.
The Guardian had previously reported that Mr Zahawi paid back tax he had owed, as well as a 30% penalty, with the total settlement amounting to £4.8million.
The tax was related to a shareholding in YouGov, the polling company he co-founded in 2000 before he became an MP.
- The UK Government has insisted all the correct processes were followed in the appointment of the BBC's chairman, Richard Sharp, in early 2021.
It follows claims that, shortly before being given the job, Mr Sharp helped the then-Prime Minister, Boris Johnson, secure a loan agreement.
The BBC reports that Mr Sharp, Mr Johnson and the government all deny there was a conflict of interest.
But Labour has asked the parliamentary standards watchdog for an inquiry.
Labour is suggesting that Mr Johnson could have breached the code of conduct for MPs "through failing to appropriately declare the arrangement" on his Parliamentary register of interests.
According to the Sunday Times, which first reported the claims, Mr Sharp was involved in helping to arrange a guarantor on a loan of up to £800,000 for Mr Johnson in late 2020.
Mr Sharp said he had "simply connected" people, while Mr Johnson's spokesman said the report was "rubbish" and insisted his financial arrangements "have been properly declared".
On Sunday, the Cabinet Office also rejected the accusations there had been a conflict of interest.