Around 100 current and former BBC presenters are being investigated for alleged tax avoidance.
HM Revenue & Customs (HRMC) is examining the tax records of freelance staff at the corporation who were paid via personal service companies.
Staff may have to repay unpaid tax if HMRC finds they incorrectly declared themselves as self-employed, rather than as employees.
The inquiries were revealed in a tax tribunal judgment involving newsreaders Tim Willcox and Joanna Gosling. They have appealed against a ruling by HMRC to pay extra tax and National Insurance contributions.
Jennifer Henderson, head of global mobility and employment tax at the BBC, told the tribunal that by the northern autumn last year the number of inquiries into cases had risen to 100.
In a statement published on the BBC News website, the corporation said it was "up to individuals to ensure they pay the right tax".
