By Donna Borak, CNN

Senate Democrats pressed Treasury Secretary Steven Mnuchin about his financial holdings on Thursday, calling on the former financier to explain why there have been delays in certifying his required ethics disclosures.

The government's chief ethics watchdog agency has yet to certify Mnuchin's 2018 financial disclosure, which was filed more than eight months ago.

The delay in certification of Mnuchin's forms by the Office of Government Ethics was first reported last week by the nonprofit Center for Public Integrity.

Sen. Ron Wyden, the top Democrat on the Senate Finance Committee, asked the Treasury secretary at the Senate Finance hearing whether he had completely shed his interest in film production company, StormChaser Partners, founded by his wife, Louise Linton.

"What we have wondered is if there has been an exchange of an asset for a loan rather than a divestment," Wyden asked.

Mnuchin responded that he has complied with rules according to certified career ethics officials inside the Treasury Department.

"I am advised by people at Treasury that I am fully in compliance and I have no ethical issues," Mnuchin said.

The secretary declined to go into specifics about particular divestments of assets, but said that career staff at Treasury had been in ongoing discussions with OGE.

"I'm in compliance, I have been certified, and I look forward to them resolving whatever issues there are between them and OGE," Mnuchin told reporters following the hearing.

The Treasury secretary sold his film and real estate businesses in 2017 for at least $15 million to avoid conflicts of interest.

An OGE spokeswoman declined to comment when asked about Mnuchin's disclosures.

The office did, however, say deadlines for certification have been extended because of the partial government shutdown earlier this year, to April 5.

Trump's top finance chief is not the only member of Trump's cabinet waiting on ethics certifications.

Last month, Commerce Secretary Wilbur Ross was found to have violated his ethics agreement, while also submitting an inaccurate financial disclosure form, according to OGE.

OGE Director Emory Rounds wrote at the time that Ross reported in his annual financial disclosure that he sold bank stock that other reports indicate he did not sell.

Ross asked House Democrats before testifying Thursday if he could address questions in writing about his inaccurate financial report rather than be questioned in public. The Washington Post reported earlier this week that the request was granted by the Democratic chairman of the committee, Rep. Elijah Cummings.