Quang, chairman and founder of private food producer Masan Group, made it to the billionaire list of Forbes magazine for the first time last March and became the 1,717th richest person in the world with a net worth of $1.3 billion.

According to updates from Forbes on Wednesday, Quang’s total assets were estimated at $980.8 million, down 25 percent since last March. This data is updated based on the changes in the price of MSN shares on the stock exchange, which account for the majority of Quang's assets.

The value of MSN shares of Masan Group have recently plummeted, leading to a decline in the value of assets of one of the richest men in Vietnam. At the end of Wednesday’s trading session, an MSN share was worth VND55,700 ($2.4), losing more than 26 percent of its value compared to a month ago.

MSN's value began falling following an announcement by Vietnam’s biggest private conglomerate Vingroup on December 3 that it had reached a deal with Masan to merge their retail subsidiaries to form a new company.

Foreign investors have been selling MSN shares on and off for a month now, which analysts at VNDIRECT Securities attributed to them possibly getting wind of what was brewing.

Quang founded Masan in 2004. The company is a major producer of fish sauce and packaged foods in Vietnam.