to save more for retirement. This provision is enforced via "non-discrimination testing". Non-discrimination testing takes the deferral rates of HCEs and compares them to NHCEs. In 2008, an HCE was defined as an employee with compensation greater than $100,000 in 2007, or as an employee that owned more than 5% of the business at any time during the year or the preceding year. In addition to the $100,000 limit for determining HCEs, employers can elect to limit the top-paid group of employees to the top 20% of employees ranked by compensation. That is, for plans with the first day of the plan-year in the 2007 calendar year, HCEs are employees who earned more than $100,000 in gross compensation (also known as 'Medicare wages') in the prior year. For example, most testing done in 2009 was for the 2008 plan-year, which compared 2007 plan-year gross compensation to the $100,000 threshold in order to determine who was an HCE and who was an NHCE. The threshold was $125,000 for 2019, and is $130,000 for 2020. 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. The annual contribution percentage (ACP) test is similarly performed but also includes employer matching and employee after-tax contributions. ACPs do not use the simple 2% threshold, and include other provisions which can allow the plan to "shift" excess passing rates from the ADP over to the ACP. A failed ACP test is likewise addressed through return of excess, or a QNEC or qualified match (QMAC). There are a number of "safe harbor" provisions that can allow a company to be exempted from the ADP test. This