when dtc chills or freezes a security it will issue a participant notice to its participants these notices are publicly available on dtc s website when securities are frozen dtc provides optional automated notifications giving participants the ability to update their systems to automatically block future trading of affected securities in addition to alerting participant compliance departments 
the bottom linethe depository trust company dtc is a limited purpose trust company and subsidiary of dtcc it provides safekeeping through electronic record keeping of securities balances and acts as a clearinghouse to process and settle trades in corporate and municipal securities 