David Ellison's Paramount would owe more than $1 billion to WBD shareholders based on the March trial date a judge set

Paramount Skydance CEO David Ellison's company may soon have to pay up to WBD investors. Gabe Ginsberg/Getty Images Paramount Skydance's financial backers may soon owe billions to WBD shareholders. The trial for Paramount's proposed merger with WBD will start on March 2, a federal judge ruled. Paramount agreed to pay WBD investors about $7 million per day that its deal isn't closed, starting September 30. David Ellison and his billionaire father may need to get their checkbooks…