Cao Thi Ngoc Suong’s ownership has fallen from 4.27% to 2.78%, according to a company filing, which did not specify why she was forced to sell the NVL shares.
A brokerage typically requires shares to be sold if it issues a margin call and the investor is unable to cough up the money.
Suong’s sale was estimated to be worth VND1.2 trillion ($48.5 million) based on Tuesday’s closing price.
Nhon’s son Bui Cao Nhat Quan recently sold five million NVL shares to reduce his stake from 4.27% to 4.13%.
NovaGroup also said it sold over 12.7 million NVL shares a week ago.
The share fell for 18 straight sessions until last Friday, 17 of them to the floor.
Brokerages said NovaGroup, the biggest stakeholder in Novaland, has found a buyer for 150 million NVL shares in December, and this has helped end its losing streak.