Adelson, who kept former U.S. House Speaker Newt Gingrich's campaign alive with $21 million during the Republican primary, will provide the largest single donation to the Romney campaign, sources told The Wall Street Journal.
Forbes ranks Adelson, chairman and chief executive of Las Vegas Sands Corp., among the Top 10 wealthiest Americans, with a net worth topping out at more than $20 billion.
Romney, a former Massachusetts governor and the likely GOP presidential nominee, by law cannot coordinate his campaign with the independent political action committee. He met privately with Adelson in Las Vegas in May, after which Adelson joined Romney at a $50,000-per-head fundraiser.
Notable deaths of 2014 [PHOTOS]