The actual deferral percentage (ADP) of all HCEs as a group cannot exceed 2 percentage points greater than all NHCEs as a group. This is known as the ADP test. When a plan fails the ADP test, it essentially has two options to come into compliance. A return of excess can be given to the HCEs to lower the HCE ADP to a passing level, or it can process a "qualified non-elective contribution" (QNEC) to some or all of the NHCEs in order to raise the NHCE ADP to a passing level. A return of excess requires the plan to send a taxable distribution to the HCEs (or reclassify regular contributions as catch-up contributions subject to the annual catch-up limit for those HCEs over 50) by March 15 of the year following the failed test. A QNEC must be vested immediately.