Employer contributions made to a qualified plan are:

Employer contributions made to a qualified plan are subject to vesting requirements. This means that the contributions made by an employer typically increase an employee's ownership of those contributions over time, according to a predetermined schedule. Vesting is designed to encourage employee retention by rewarding employees who stay with the company longer.

In a qualified retirement plan, these contributions are made on a pre-tax basis, and employees do not have immediate access to them until they meet the vesting requirements or reach retirement age, which further underscores the importance of these requirements in the context of employee benefits.

The other options do not accurately describe the nature of employer contributions to qualified plans. For instance, employer contributions cannot discriminate in favor of highly compensated employees, as qualified plans must meet certain non-discrimination regulations. Additionally, these contributions are made pre-tax, not after-tax, and they are not taxed annually as salary until withdrawn from the plan in retirement. Thus, the primary characteristic of employer contributions to a qualified plan is indeed their subjectivity to vesting requirements.