Delisting requirements vary from one exchange to the next.
New York Stock Exchange (NYSE)
On the New York Stock Exchange (NYSE), if a security’s price closes below $1.00 for 30 consecutive trading days, that exchange would initiate the delisting process. If a ticker the letters “BC” attached indicate the stock is non-compliant. But such companies may continue trading normally on the exchange during their probationary periods. Probationary periods are the time they have to become compliant with the rules.
American Stock Exchange (AMEX)
If your stock falls below $1 a share or you don’t file your corporate financial documents timely, your stock qualifies for delisting from AMEX. Other reasons for delisting include your stock is thinly traded and having too few stock owners. After AMEX contacts you about delisting, you have 45 days to file a plan to show how you will correct the problem. If AMEX does not accept your plan, the exchange will proceed with the delisting process.