Key employee, along with HCE, is another classification that the IRS uses to ensure a pension or welfare benefit plan isn’t becoming too “top-heavy.” A key employee is an HCE with slightly higher thresholds.
Key Emp Definition 2022(https://www.dwc401k.com/knowledge-center/who-are-highly-compensated-and-key-employees) defines the thresholds, which are adjusted for inflation annually.