Four Pacific Island countries have been identified by Azerbaijan as financial offshore centres from where no company can operate in the country's securities market.
Financial offshore centres are small, low-tax jurisdictions specialising in providing corporate and commercial services to non-resident companies offshore for investment.
The government's decision to limit the countries where shareholders may be based is seen as part of efforts to halt the illegal outflow of capital.
Nauru, the Cook Islands, Vanuatu and Samoa are on a list of 15 countries or territories blacklisted as a base for shareholders active in Azerbaijan.
The other offshore centres include Panama, the Dutch Antilles and the US Virgin Islands.
According to Russian media an estimated $US50 billion was transferred illegally from Azerbaijan to off-shore centres in 2014 alone.