Wang, 57, suffered serious injuries after falling Tuesday while on a business trip in Provence, France, HNA said.
Wang was second only to Co-Chairman Chen Feng within HNA's hierarchy, and owned about 15 percent of the conglomerate, making him one of the group's biggest shareholders, according to HNA's last update of its ownership structure.
Wang died after a 10 meter fall off a wall, the source said. Wang fell from the wall in Bonnieux whilst having his picture taken. Mr. Wang started his career as an aviation official and co-founded HNA with Mr. Chen more than two decades ago.
The company turned its website grey to representing mourning.
Chinese tycoon Wang Jian has died in France in freaky circumstances while on a sight-seeing trip.
But, under pressure from Beijing, HNA has sold off many of its prime assets to slash debt, with recent sales including holdings in companies such as Hilton Worldwide Holdings Inc, Park Hotels & Resorts and Spain's NH Hotels.
He said Mr Wang fell some 15m (50ft).
"It will also put HNA Group and related companies' restructuring plans back on the drawing board, in our view", Png added.
"If HNA simply can not meet its financial obligations, we expect regulators to broker a debt restructuring", Michael Hirson, the Asia director of the consultancy Eurasia Group, said back in February.
Naturally, Wang was instrumental in building this corporate empire, with a labyrinth of domestic entities such as HNA Aviation & Tourism, HNA Logistics, HNA Capital and HNA Technology, and was part of the process of slimming down a bloated organization.
Another police source told The New York Times that Wang's death was being investigated but that the police had no immediate suspicions of foul play.
In April, HNA disclosed plans to sell at least some of its more than $6.5 billion stake in hotel operator Hilton Worldwide Holdings Inc., according to a USA regulatory filing.
However, the deal had looked increasingly uncertain because of liquidity problems that have seen HNA shed more than $20 billion of assets to pay down debt. Borrowing costs soared as its interim report showed the conglomerate paid the highest interest expense among non-financial companies in Asia, a trend that continued through 2017.