"Moreover, the ECC’s policies and procedures expressly instruct staff, as a general matter, not to forward for further investigation complaints based on data obtained from “Level II” trading terminals. Because many investor complaints of naked short selling are based on information obtained from Level II trading screens, no triage is performed on these complaints and they are automatically not forwarded to Enforcement staff, unless they pertain to an existing Enforcement matter. "
Page 6 of the PDF
www.sec-oig.gov/Reports/AuditsInspections/2009/450.pdf