If a company PPS is below $1.00 for 30 consecutive days, they receive a letter of notification of possible delisting. At this time, the company can prove their worthiness to adhere to the rule and get an extension of 180 days. If they fail to do so but other requirements are meant for "compliance" they can get another 180 days.
For example BCON shares were above $1.00 for the last 10 consecutive business days and thus received a "Compliance Letter"
Beacon Power Announces Compliance with NASDAQ Continued Listing Requirements Thursday July 5, 9:00 am ET
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