For calendar year plans, the 2015 plan year Form 5500 is due to be filed electronically no later than August 1, 2016. ERISA requires that Form 5500 be filed with the Department of Labor for most health and welfare plans (for example, medical, dental, and life insurance plans) by the last day of the seventh month following the end of plan year unless an extension (Form 5558) is completed and mailed to the IRS.