Altairnano just announced that it has received notice from the NASDAQ stock exchange it is in violation of Rule 5550(a)(2) because its stock price fell below a $1.00 from November 9 through December 1st.
The company has a 180-day grace period to bring its share price back up above $1.00 for at least 10 business days in a row. After that, it may be eligible for an additional 180-day grace period or it may be delisted (with an option to appeal).
According to this press release, the company will monitor the situation as it looks for ways to bring itself back into compliance.