Kolomoisky, one of Ukraine's richest men and a so-called oligarch, was ordered into custody on suspicion of money laundering last week, and, according to media reports, is being treated as a suspect in an embezzlement case.
A lawyer for Kolomoisky did not immediately respond to written requests for comment about asset seizures. The tycoon's lawyers have not commented on the embezzlement case. Kolomoisky has denied wrongdoing in the past.
The National Anti-Corruption Bureau of Ukraine (NABU) said it had frozen more than 3 billion hryvnia in assets in addition to nearly 1,000 properties and more than 1,600 vehicles and vessels from the former owner of lender PrivatBank.
The NABU statement did not name Kolomoisky.
Kolomoisky is a former owner of PrivatBank, which was nationalised in late 2016 as part of a clean-up of the Ukrainian banking system.
He is among the tycoons who built their fortunes in the ashes of the Soviet Union and amassed political power in Ukraine's fragile post-Soviet democracy.
The moves against him come as Kyiv is trying to signal progress during a wartime crackdown on corruption that is important to its hopes of joining the European Union.
Ukrainian officials have also said that "de-oligarchisation" is an important step to building a stronger state after the war with Russia.
(Reporting by Yuliia Dysa and Dan Peleschuk; writing by Tom Balmforth; editing by Timothy Heritage and Mark Heinrich)
