Aimlon CPA P.C. | Key 2026 U.S. Tax Deadlines for Businesses and Individuals

Staying informed of U.S. tax deadlines is a key compliance and planning requirement for businesses and individuals operating in an international environment. The Internal Revenue Service (IRS) has confirmed that the filing season for 2025 individual income tax returns will open on January 26, 2026.

This article outlines the principal U.S. federal tax deadlines for 2026, with a focus on issues commonly faced by French and European executives, entrepreneurs, and individuals established in the United States. For cross-border businesses and internationally mobile taxpayers, anticipating filing obligations and estimated tax payments is essential to maintaining compliance and managing risk.

Tax Deadlines for Businesses

January 15, 2026

· Payment of the 4th estimated income tax installment for tax year 2025 for self-employed individuals, independent contractors, and partners or shareholders of pass-through entities.

February 2, 2026

· Filing of Forms W-2 and 1099-NEC MISC:

o Employers must provide employees with Form W-2 and file copies with the Social Security Administration (SSA).

o Businesses must report compensation paid to independent contractors using Form 1099-NEC MISC, and provide a copy to each recipient.

March 2, 2026

· Deadline to file Forms W-2 and 1099-NEC if an extension was requested.

March 16, 2026

· Filing deadline for:

o Partnerships (Form 1065)

o S Corporations (Form 1120-S) (Entities with a December 31 fiscal year-end)

April 15, 2026

· Payment of the 1st estimated income tax installment for tax year 2026 for self-employed individuals and pass-through entities.

· Filing deadline for C Corporations (Form 1120) with a December 31 year-end.

May 15, 2026

· Filing deadline for tax-exempt organizations (Form 990) with a December 31 year-end.

June 15, 2026

· Payment of the 2nd estimated tax installment for 2026.

September 15, 2026

· Extended filing deadline for pass-through entities.

· Payment of the 3rd estimated tax installment for 2026.

October 15, 2026

· Extended filing deadline for corporate income tax returns (C Corporations).

December 15, 2026

· Payment of the 4th corporate estimated tax installment for corporations with a December 31 year-end.

January 15, 2027

· Payment of the 4th estimated income tax installment for tax year 2026, unless the 2026 return is filed by January 31, 2027 and the balance due is paid at that time.

Most U.S. states generally align their tax deadlines with federal IRS deadlines.

Tax Deadlines for Individuals

April 15, 2026

· Filing deadline for individual income tax returns:

o Forms 1040, 1040-SR, or 1040-NR, as applicable

o Estate and trust income tax returns (Form 1041)

June 15, 2026

· Filing deadline for U.S. taxpayers living and working outside the United States and Puerto Rico, including U.S. military personnel stationed abroad.

October 15, 2026

· Extended filing deadline for individual income tax returns if an extension was requested.

 

Key Figures on U.S. Federal Taxation

· $5.1 trillion in federal taxes collected for the fiscal year ended September 30, 2024.

· 86% of total revenue came from individuals and payroll taxes:

o Individuals: $2.8 trillion

o Businesses: $565 billion

o Payroll taxes: $1.7 trillion

· $552.7 billion in tax refunds issued by the IRS.

· 267 million tax returns and information forms processed.

· Individual income tax returns represent approximately two-thirds of all filings.

 

European founders, executives, and business owners operating in the United States face unique compliance and planning challenges. Meeting U.S. tax deadlines is not only a compliance requirement but also a strategic consideration, particularly in an international context involving subsidiaries, holding structures, independent activities, or non-profit organizations.

A well-structured tax calendar supports compliance, cash-flow management, and risk mitigation in a complex regulatory environment.

 

Anticipate rather than correct

Effective management of tax deadlines helps avoid penalties and interest while supporting sound tax planning—especially in a cross-border environment.

For European executives, entrepreneurs, and individuals based in the United States, tailored guidance can help secure U.S. tax compliance while addressing broader international tax considerations between France and the United States.

 

Author:
• Mathieu Aimlon, Principal, AIMLON CPA P.C.

Compliments of  Aimlon CPA P.C. – a member of the EACCNY