Net assets are assets owned by enterprises and can be freely controlled, that is, owners' equity. It consists of two parts, one part is the capital invested by the enterprise at the beginning, including the premium part, and the other part is created by the enterprise in its operation, including the donated assets.
Negative net assets are generally caused by huge losses of enterprises. When undistributed profits (including profits of this year and previous years) are negative and the amount is greater than "paid-in capital+capital reserve+surplus reserve", the net assets are negative.