The Broadcasting Authority of Ireland has discussed Denis O'Brien's media holdings including his share in INM and has decided that no action is to be taken by the regulator at this stage.
Mr O'Brien's company Communicorp controls, or has substantial interests in six independent radio stations in Ireland.
Last May he increased his share in the Independent News and Media newspaper group to 29.9%.
In a statement, the BAI has said it has a statutory obligation to consider the desirability of allowing any person or group of persons to have control of, or substantial interests in an undue amount of communications media.
However at its board meeting on Monday, it determined that Mr O'Brien does not "control" INM, rather he has a substantial interest in the company.
The Authority said that, in this regard it was not obliged to review Mr O'Brien's interests in the context of an undue amount of communications media.
The regulator also said it considered it noteworthy that Mr O'Brien's interest in IN&M has been enhanced, that the situation regarding the Company is fluid and that it is intended that further appointments be made to its board of directors.
Communicorp has been requested to ensure that it keeps the Authority fully informed of all developments in this regard.