Effective in 2024, Form 5558 is no longer used to apply for an extension of time to file Form 5330, Return of Excise Taxes Related to Employee Benefit Plans. Instead, use Form 8868, Application for Extension of Time To File an Exempt Organization Return or Excise Taxes Related to Employee Benefit Plans, to apply for an extension of time to file Form 5330.
For the latest information about Form 8868 and its instructions go to IRS.gov/form8868.