Ukraine has adopted a new law aimed at limiting the influence of oligarchs on national politics.
The legislation will prevent wealthy individuals from funding political parties or taking part in the privatisation of state assets and major companies.
The bill requires Ukrainian citizens to register as oligarchs if they own significant financial assets and media outlets. The law also requires senior state officials to declare any dealings with oligarchs.
The law passed its first reading in July and was approved by 279 lawmakers in the Ukrainian Parliament on Thursday.
President Volodymyr Zelenskyy, who has backed the law, will now sign it into effect.
The country's former president and candy tycoon Petro Poroshenko may be affected by the legislation, as well as businessman Igor Kolomoysky, who backed Zelenskyy at the 2019 election and controls Ukraine's most popular TV channel, 1+1.
The law against oligarchs comes just one day after the car of a top aide to Zelenskyy came under gunfire near Kyiv.
The Ukrainian President has suggested that the assassination attempt could have been triggered by the reform. Police have said they were focusing on political leads.
Zelenskyy has promised a "strong response" to the attack and vowed to continue his "fight against crime and against influential financial groups."
According to the Ukrainian parliament, the new law aims to prevent "threats to national security related to the excessive influence of persons of significant economic and political importance in public life".
"The purpose of this law is to overcome the conflict of interests caused by the merger of politicians, media and big business."
Earlier this year, President Zelensky announced a campaign against corrupt businessmen, who are long accused of exploiting Ukraine's economy and buying the votes of the media and the political class.
"Ukraine is open to big business, but not to oligarchic influence on officials, politicians, and the media," Zelenskyy tweeted on Thursday. "Today we have taken another step towards getting rid of it."
But critics have feared that the law will be applied selectively to help concentrate more power in the president's own hands.