One of the most common – and most expensive – misconceptions in tax compliance is the assumption that a filing extension also delays the payment obligation. An extension typically provides additional time to submit the return, but not to settle the underlying tax liability. Understanding this distinction is essential, particularly in cross-border situations where different systems apply very different levels of flexibility.
In the United States, filing extensions are a well-established and widely used compliance tool. Individual taxpayers are required to file their federal income tax return (Form 1040) by 15 April, but they may request an automatic extension until 15 October by submitting Form 4868.
What does not change, however, is the payment deadline. Regardless of the extension, taxpayers are expected to settle their estimated tax liability by 15 April. To figure your estimated tax, you must figure your expected adjusted gross income, taxable income, taxes, deductions, and credits for the year. Generally, most taxpayers will avoid the penalties if they owe less than $1,000 in tax after subtracting their withholdings and credits, or if they paid at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller. If these thresholds are not met, interest begins to accrue from April, and underpayment penalties may apply under the Internal Revenue Code.
The U.S. penalty framework also clearly separates filing and payment failures. Late filing may trigger a penalty of 5% per month (capped at 25%). If fraud, 15% of balance due per month or part of month, up to 75% of balance due. Late payment typically results in a 0.5% monthly charge, also capped at 25%.
In practice, this means that even when a taxpayer properly files for an extension, a poorly estimated tax position can still lead to significant financial exposure.
Hungary, by contrast, follows a much stricter and less flexible approach. For individuals, the personal income tax (SZJA) return must be filed by 20 May following the tax year. In many cases, the tax authority (NAV) prepares a return draft, which becomes final if the taxpayer does not amend it. Unlike the U.S. system, there is no automatic extension mechanism available.
The payment obligation is also tied to the same 20 May deadline. Failure to comply may result in late payment interest based on the Hungarian central bank base rate, as well as a tax penalty that is generally 50% of the tax shortfall and may increase to 200% in more severe cases. From a practical perspective, this means that Hungarian tax compliance leaves little room for timing strategies, deadlines are fixed. In addition to tax penalties, Hungarian law also allows for the imposition of default penalties. Unless otherwise provided by law, the tax authority may impose a default penalty of up to HUF 400,000 on individual taxpayers and up to HUF 1,000,000 on non-individual taxpayers for breaches of tax obligations.
A breach is deemed to occur not only in cases of non-compliance, but also where the obligation is fulfilled incorrectly, incompletely, with false data content, or with delay.
There are, however, certain special regimes in the United States that provide broader relief. Taxpayers living abroad automatically receive an additional two months to file, extending their deadline to 15 June, although interest on unpaid tax still runs from April. Even more extensive relief is available for military personnel serving in combat zones, where both filing and payment deadlines may be suspended, followed by an additional 180-day period after leaving the zone. This extension begins after the last day in the combat zone or last day of continuous qualified hospitalization.
In cross-border practice, filing extensions often become particularly relevant. Delays in receiving foreign income documentation, partnership information such as Schedule K-1, or data from trust and holding structures are common. In such cases, the extension allows taxpayers to take a more accurate and defensible reporting position. The real risk, however, lies in the estimation process. Underestimating the liability can trigger penalties and interest, while overestimating it may create unnecessary cash flow pressure.
For this reason, extension planning should always be supported by conservative assumptions, proper documentation, and a conscious approach to liquidity management. Ultimately, filing extensions are best understood as a procedural tool rather than a financial one. They provide flexibility in reporting, but they do not eliminate exposure arising from late payment.
Whether operating under the flexible U.S. system or the stricter Hungarian framework, the underlying principle remains the same: filing can wait, but payment cannot.
Disclaimer
This article is provided for general informational purposes only and does not constitute tax or legal advice. The analysis is based on the legislation and administrative guidance in force at the time of writing, which may be subject to change. The application of tax rules depends on the specific facts and circumstances of each case, particularly in cross-border situations. Readers should seek professional advice before taking any action based on the information contained herein.
Note
For readers dealing with Hungarian tax matters or relocation-related questions, further information and practical guidance are available at www.relocationtax.com. Professional assistance can also be provided where needed.
Sources
- Internal Revenue Code (IRC)
- IRS, Form 4868 – Application for Automatic Extension of Time to File U.S. Individual Income Tax Return
- IRS, Form 7004 – Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns
- IRS, Publication 505 – Tax Withholding and Estimated Tax
- IRS, Publication 54 – Tax Guide for U.S. Citizens and Resident Aliens Abroad
- Act CXVII of 1995 on Personal Income Tax (Hungary)
- Act CL of 2017 on the Rules of Taxation (Art.)