What is the main reason unions adopt money purchase plans?

Unions often adopt money purchase plans primarily to ensure certainty of contributions. This type of retirement plan mandates a specific contribution amount that must be made by the employer into the plan each year, regardless of the company's profitability. This structure provides employees with a clear understanding of the retirement benefits they can expect to receive, as contributions are fixed and predictable. This certainty can be especially important for unions, which aim to secure stable retirement benefits for their members.

By contrast, while providing more investment options, allowing for easy withdrawal, or minimizing administrative costs are relevant considerations for retirement plans, they do not encapsulate the fundamental appeal of money purchase plans in the union context. The emphasis is on the guaranteed nature of contributions which aligns with the unions' goals of providing reliable financial security for their members in retirement.