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I am familiar with the Form 5500, the Annual Return/Report of Employee Benefit Plan. This is actually a Department of Labor form, not an IRS form. You do not file it with your plan administrator. You have to electronically file it directly with the Department of Labor.
The 401(k) provider, whether T Rowe Price, AXA, Pershing, or any of the other big plan administrators/managers will provide you with the information that is required for filing the return.
If you need to amend a previously filed return, you need to file it electronically as well. You can go to:
They have information on filing amended returns
. Click on the FAQ under Support on the left side menu. Then choose Electronic EFAST2 FAQ. There is an item, Q4, addressing amended returns.
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