A company profiting from a new North Carolina tribal casino gave shares to politicians family members and high-profile political figures as the casinos backers were seeking federal approval for the project, according to interviews and documents reviewed by The Wall Street Journal.

One of the stakes is held by John B. Clyburn, a brother of Rep. James Clyburn, the powerful South Carolina Democratic congressman who introduced a bill in Congress last year that smoothed the way for the new Catawba Two Kings Casino.