Trump adviser Jared Kushner allegedly failed to disclose his ownership interest in an online real estate investment company, according to an ethics complaint filed Thursday.

Per the complaint — filed by Citizens for Responsibility and Ethics in Washington – to the Office of Government Ethics, President Trump's adviser and son-in-law did not disclose his ownership of a "significant part" of Cadre, a technology company that he co-founded. Additionally, when he requested his certificate of divestiture, he liked failed to disclosed to disclose his ownership interest in the company, resulting in the certificate being granted with incomplete information.

The certificate, which allows federal employees to defer capital gains taxes on property they sell to meet ethics codes, likely would compel Kushner to sell his interests in the company.

"Kushner's failure to disclose his ownership in Cadre is very troubling," CREW executive director Noah Bookbinder said in a statement. "It appears to be one of his larger investments, not something he could easily overlook, and it is impossible to ensure that senior government officials are behaving ethically if they fail to disclose key assets.

Cadre was founded in 2014 by Kushner, his brother Josh Kushner and Ryan Williams. The e-commerce site provides real estate investment opportunities. According to the complaint, the company was worth more than $800 million as of June.

It is unclear how much of the company is owned by Jared Kushner, per the complaint.

"Nevertheless, Mr. Kushner's representatives recently reconfirmed his ownership interests in the company," the complaint reads.

Read the full complaint here.