Fidelity has issued a warning to employees who leave a 401(k) at an old job after switching jobs, stating that it could be costing them thousands of dollars. The financial giant has outlined four options for handling that old account, which could save you thousands over time but potentially trigger penalties, taxes, and missed growth. The advice includes leaving the money in your former employer’s plan, rolling it into an IRA, and consolidating it into your current workplace plan. However, some plans limit withdrawal flexibility and may result in penalties. Fidelity's guidance also includes reviewing the new company’ financial structure and potential tax benefits.