Secretary of Commerce Wilbur Ross owns holdings in a shipping company that has business ties to a Russian gas company part-owned by Russian President Vladimir Putin’s son-in-law, according to several reports published Sunday.

The Guardian reported, citing documents and public filings from the Paradise Papers, a trove of 13.4 million files leaked from offshore law firm Appleby, that Ross has a stake in the shipping company Navigator, which operates a partnership with Russian gas company Sibur.

Putin’s son-in-law Kirill Shamalov is Sibur’s second-largest shareholder.

NBC News reported, citing documents from the Paradise Papers, that Sibur is Navigator’s second-largest client.

According to the Guardian, Ross retained his holdings in Navigator after joining Trump’s cabinet.

Ross in February did not answer questions from six Democratic senators who asked him to disclose “the full extent” of his “connections to Russia.”

Hours after Trump nominated Ross to his cabinet in November 2016, Navigator’s CEO David Butters said Ross assured him their interests were aligned.

“Your interest is aligned to mine,” Ross said, according to Butters’ account to Bloomberg Businessweek. “The U.S. economy will grow, and Navigator will be a beneficiary.”