Investors and ex-employees of China’s HNA Group Co. who bought investment products from a unit of the conglomerate protested outside the company’s headquarters in the southern province of Hainan this week, accusing it of taking their money and not returning it, according to people familiar with the matter.
The incident followed a recent decision by an HNA-backed online lending and investment platform to stop selling financial products to retail investors. The platform informed investors in recent days that they would have...