For many Americans leaving their current jobs, a 401k rollover is an important step in maintaining maximum control of their investments. When you leave a job, or a qualified 401k plan is terminated, a 401k rollover is a special arrangement that allows you to have better control over your future investment choices. The 401k rollover allows you to transfer funds to a new qualified retirement plan or be distributed to the employee, rather than leaving them as part of the past 401k plan. As with all financial transactions, a 401k rollover must be planned for, and done carefully.