U.S. Department of Commerce Secretary Wilbur Ross told CNBC that he shorted shares of two companies in May 2017, an acknowledgement that follows reports last month that he had shorted a shipping company's stock after learning a potentially negative story about his dealings with the firm was being prepared.

"These transactions are not profit-seeking short sales," Ross told CNBC, which reports that Ross shorted the stock of Air Lease Corp. and Ocwen Financial Corp. "These shorts are technical ways of disposing the stocks."

Ross said all the trades were approved after execution by the Commerce Department's office of ethics and compliance, according to CNBC.

The news comes as the Trump administration is set to impose tariffs on Chinese imports on July 6 after already imposing tariffs on imported steel and aluminum from Canada, Mexico and the European Union, moves that drew retaliatory measures. The steel and aluminum levies were put in place after a Commerce Department review.