The two parties are expected to sign an agreement on the deal by the end of this month.
Variety offers five possible reasons for the sale, including a reduction of the (possibly massive) debt incurred during Wanda's global spending spree over the last few years, avoidance of the growing regulatory scrutiny in China, and competition from Disney.
With the latest deal, Sun targeted assets from fellow-billionaire Wang Jianlin, who was among the most acquisitive Chinese tycoons up until past year.More news: NBA Summer League tips off in Las Vegas
The CBRC had expressed concerns about the level of debt taken on by some of China's biggest groups, against a background of skyrocketing debt at corporate level.
The deal highlights a quandary being faced by Chinese corporations that bet big on overseas acquisitions but now face difficulty paying off debts.
"This (deal) signifies a retreat from Wanda's previous strategy in cultural tourism, and marks a pivot to an asset-light strategy", said Qin Gang, senior researcher at State Information Center, a government-linked thinktank. It doesn't mean their businesses are in trouble. This fake Lamborghini is a 'Shanzhai' model of the kind that are growing in demand in China, where you can get a smart vehicle knock-off of a Land Rover, a Mercedes-Benz, or a BMW.More news: Tillerson says United States ready for Syria no-fly zone with Russian Federation
Wanda, a commercial property developer that has diversified into entertainment, theme parks, and sports - partly as a buffer against Chinese real-estate volatility - was at the forefront of the overseas push, spending billions on a range of U.S. entertainment properties and other investments.
Wanda had earmarked a more than 300 billion yuan investment for its cultural and tourism projects. It did not comment further on the deal. Earlier this year, it threw a lifeline to Beijing-based LeEco Holdings, investing $2.2 billion in the troubled tech and entertainment company.
Sunac yesterday halted trading of its shares in Hong Kong pending an announcement of a "very substantial" acquisition, it said.More news: Saudi FM: Qatar boycott to remain until Arab states' demands met