When investing in the stock market, you would have heard of the term public listing. Essentially, that refers to a company being listed on the stock market for public ownership. Companies do this on a voluntary basis. There are occasions when they are “delisted” from the stock exchange. Delisting can be voluntary or involuntary.
An involuntary delisting is usually imposed by the exchange due to eg. Flouting exchange rules or company going bankrupt.
A voluntary delisting is initiated by the company for various reasons – eg. Mergers and acquisitions.
Check out this article for details.