Companies that fail to file a Form 10-Q or 10-K on time are required by SEC Rule 12b-25 to file a Form NT (for “Non-Timely,” also known as Form 12b-25) no later than one day after the due date. Timely filing of Form NT results in an automatic one-time grace period of five days for 10-Qs and 15 days for 10-Ks. Form NT also requires management to explain the reason for the late filing and declare whether it expects to subsequently file within the allowed grace period. Companies that file Form NT on time and subsequently file within the allowed grace period are considered by the SEC to have complied with rules and avoid SEC-imposed penalties.[1] Conversely, companies that fail to file within the allowed grace period are subject to a variety of costly penalties, including deregistration by the SEC, delisting by stock exchanges, the inability to raise capital through issuance of public securities, and potential debt covenant violations.[2]
http://clsbluesky.law.columbia.edu/2017/11/27/how-missing-sec-filing-deadlines-affects-a-companys-stock-value/