Final answer:
The annual QPP maximum contribution must be prorated for an employee when they start mid-year, reach the maximum at one job, retire part-way through the year, or have jobs across different provinces with varying pension plans.
Step-by-step explanation:
The annual QPP (Quebec Pension Plan) maximum contribution must be prorated when an employee starts working partway through the year, has multiple jobs where they reach the maximum contribution at one employer, works for part of the year before retiring, or when they work both in Quebec and in another province that has a different pension plan such as the CPP (Canada Pension Plan). Prorating the contribution ensures that the employee does not overcontribute to the QPP for the time that they are eligible in the year. Proration involves calculating the contribution based on the portion of the year the employee is working, rather than the full year.