According to reports in The Times, O'Brien, who earlier this week was threatened with being sued by IN&M chief executive Sir Anthony O'Reilly for publishing an allegedly defamatory report about the company, is calling for The Independent to be sold off, along with a host of Australian radio stations in order to turn around the company's sagging performance.
O'Brien paid around €31m (£21m) to up his stake in IN&M by one percentage point to 8.35% earlier this month and has been critical of its management. He is now highlighting The Independent's losses, which are believed to have been around €9m last year.
The report by O'Brien and Davis Global Advisers, which was issued in time for IN&M's annual general meeting earlier this week, could result in formal legal action by the company unless the offer of a public apology is made.
The substance of the document, which was reportedly described as "18 pages of shite" by an outspoken shareholder at the AGM, raises concerns about governance issues within IN&M, but does not allege malpractice by the board nor the executives of the company.
Stephen Davis, author of the report, said: "The firm's Achilles heel is a board composed of directors who nearly all have affiliations in some fashion with the principal shareowner, who is also the chief executive."
The Independent continues to slide in the ABC figures, posting a month-on-month circulation drop of 1.63% to 245,466, and a six-month average circulation decline of 1.83% to 251,977. However, sister title The Independent on Sunday dropped 14.46% over April to 209,418 copies, resulting in a six-month average fall of 4.4% to 226,546.