The first lady of Virginia bought and held Star Scientific stock when she and her husband Governor Robert McDonnell were promoting the nutritional supplements maker, the Washington Post reported on Saturday.
The relationship between the McDonnells and Star Scientific has been the subject of criminal investigations after loans and gifts the company's Chief Executive Jonnie Williams gave to the governor were uncovered.
Bill Burck, an attorney for first lady Maureen McDonnell, told the Post she purchased 6,000 shares of Star Scientific stock on June 1, 2011, the day she publicly voiced her support for the company at a gathering of physicians and investors.
The first lady's purchase, which amounted to about $30,000, came a few days after Williams wrote a $50,000 check to her, according to the paper.
Burck also disclosed to the paper that Maureen McDonnell bought another 522 shares for about $2,000 two months later, the same day that she set up a meeting between Williams and a state health official.
The Washington Post said the first lady, a few weeks after the meeting between Williams and the official, hosted a luncheon at the governor's mansion for the company's launch of a product, an event attended by the governor.
Burck said she sold the shares in December, 2011, for a loss and then used the proceeds to buy 6,672 shares in January, 2012.
The governor's annual statement of economic interest did not disclose the ownership, as required by law, according to the newspaper.
In July, McDonnell said his family had repaid more than $123,000 in loans to Williams and apologized for the embarrassment that it had brought the state.
Williams has given a number of gifts to the governor's family, including $15,000 in catering for the wedding of the governor's daughter and a watch to the first lady, according to local media.
Federal and state authorities are probing the relationship between the McDonnells and Williams.
There was no response on Saturday to a phone call to the governor's communications office.
(Editing by Barbara Goldberg and Eric Walsh)