According to the ethics watchdog, the probe was expended in response to information provided by a journalist.
The investigation will look into whether Skvernelis included all information into his declaration of private interests and indentified all legal entities in whose activity his wife Silvija Skvernelė was engaged over the last three years.
The commission launched the probe against the prime minister in June and is looking into whether the prime minister declared in time the fact that his wife is a shareholder of Swedbank.
The probe should take place three months.
The prime minister said earlier that his wife receive Swedbank shares worth around 7,000 euros as part of a pay package.
The watchdog already ruled earlier that the head of government stated in his declaration of private interests that his wife works for Swedbank, he has a deposit in this bank, received a mortgage from this bank and has an insurance agreement with this bank, which is enough to identify a potential risk of a conflict of interests.