Brussels is taking aim at cash-for-visa or passport schemes after identifying serial abuses in schemes run by countries belong to the European Union
"We are looking at it with concern," EU justice commissioner Vera Jourova said.
Investor residence and citizens schemes offering "golden visas and golden passports" have been condemned as a weak link in anti-corruption and money laundering efforts.
Brussels believes that wealthy candidates for residency or citizenship do face insufficient security and background checks to prevent them from posing a security risk, laundering money or evading taxes.
On its shortlist for remedial action is Bulgaria, Cyprus and Malta, which run schemes granting foreign investors citizenship for anywhere between 500,000 euros and two million euros.
While most foreigners must follow a naturalisation route, investors are not required to live in those EU countries or show "genuine connections" to them.
Bulgaria has already said that it would scrap the practice.
The Commission also said residence permits given to foreign investors pose serious security risks to member states, even if the holder has fewer advantages.
Berlin-based Transparency International and London-based Global Witness welcomed the Commission's report about a practice they have repeatedly warned is flawed and poses dangers to the rule of law.
