Federal excise tax developments for 2026
Several federal excise tax developments became effective in 2026 that may impact taxpayers filing Form 720. These changes are particularly relevant for taxpayers in the fuels, ethanol and broader energy sectors.
Expiration of the OSLTF
The OSLTF tax expired on Dec. 31, 2025. As a result, the federal excise tax on crude oil and petroleum products now reflects only the Superfund financing component. For 2026, the Superfund rate has been adjusted for inflation to $0.18 per barrel. While taxpayers such as ethanol producers using natural gasoline from fractionation facilities may continue to owe excise tax, the overall rate is reduced due to the expiration of the oil spill component. Congress may choose to reinstate the oil spill tax in the future, and taxpayers should continue to monitor legislative developments.
USPS policy changes
Taxpayers should be aware of updated USPS postmarking practices, which may affect the application of the ‘timely mailed, timely filed’ rule. Effective Dec. 24, 2025, USPS updated its Domestic Mail Manual (DMM 608.11) with language that postmarks ‘do not inherently or necessarily align with the date on which the Postal Service first accepted possession of the mail piece.’ Under the updated procedure, postmarks may now reflect when mail is first processed at a regional facility, not when it was deposited with the USPS. This change may increase filing risk for Form 720 filers that mail returns or payments close to the due date. Taxpayers may wish to consider certified or registered mail, requesting a hand-stamped postmark or filing electronically where available to mitigate risk of penalties, rejected extensions or loss of refund claims.
Superfund excise tax updates
The list of taxable Superfund imported taxable products subject to tax has been expanded for 2026. Taxpayers involved in the importation of these listed imported products should evaluate whether these changes affect their excise tax obligations.
Forthcoming guidance on section 6435 dyed diesel refunds
The Treasury and the IRS have announced forthcoming guidance under new section 6435, enacted as part of the OBBBA. OBBBA section 6435 establishes a refund mechanism for federal excise tax paid on diesel fuel or kerosene that is subsequently dyed in a registered terminal and removed for an exempt use.
Prior to enactment, no such recovery mechanism existed. The IRS has indicated that it will not process refund claims under section 6435 until formal guidance is issued.
Excise remittance tax
The new federal excise remittance tax became effective Jan. 1, 2026, as enacted under OBBBA. The tax applies to certain monetary remittances and is imposed on the transfer of funds under certain conditions. Entities involved in facilitating or processing covered remittance transactions may have new excise tax collection, reporting and Form 720 filing obligations. Taxpayers potentially affected by this provision should review their transaction flows and compliance procedures to determine whether the remittance tax applies and to ensure timely reporting and payment. RSM US previously wrote an article on the remittance tax that can be referenced for more information.
