Transportation Secretary Elaine Chao has sold the stock she held at highway supply company Vulcan Materials after coming under fire for not cashing out of the options prior to joining the Trump administration, The New York Times reports. Chao—who previously served on the board at Vulcan, one of the country’s largest manufacturers of highway construction materials—sold off the shares last Monday, according to a letter released by the U.S. Transportation Department on Thursday. Chao reportedly sent a letter to an ethics lawyer at the department earlier this week announcing the sale and attributing the stock holdings to an “inadvertent misstatement.” The news came shortly after media reports raised questions about a possible conflict of interest. The shares were reportedly worth $250,000 to $500,000.