The qualifying threshold level in most countries is 10%. Most of the countries though do not have an explicit cap on the maximum shareholding by a single person/entity. The above structure applies to direct as well as indirect control by a person singly or jointly through a group of associates or related parties.
The regulators give approvals on a case to case basis subject to a number of considerations including the overall sectoral impact of the transaction and the satisfaction of ‘fit and proper’ principles by the person(s) acquiring the stake.