A. Yes. Under a 2001 tax law change, a 401(k) plan must use either three-year “cliff” vesting or a gradual vesting schedule reaching 100 percent after six years. Maybe your old company used the gradual-vesting method. But if the new company uses a plan with cliff vesting, you should be fully vested in your 401(k) after the merger, even though the length of your employment equals only four years.
Tip: You can roll over the 401(k) benefits tax-free into another qualified plan or an IRA.