The March 16 deadline just passed, and your team is probably already neck-deep in 1040s. But before you fully shift gears, there's real value in pausing to assess what worked, what didn't, and what's about to hit you in the next 30 days
This guide covers the post-March 16 debrief process, every April 15 deadline your firm needs to track, and practical strategies for managing the transition from entity returns to individual season without losing momentum.
The March 16 deadline for S corporations (Form 1120-S) and partnerships (Form 1065) acts as a bottleneck that, when handled well, sets up a smoother April 15 individual filing season. Starting March 16, most firms shift into what's often called the "April Push" phase. This means processing extensions, reviewing work in progress, and getting ahead of client communication before the "what's the status of my return" calls start flooding in.
Taking even a few hours to debrief before diving into 1040 season helps prevent the same problems from compounding over the next 30 days. The patterns that caused stress in March will repeat in April if you don't address them now.
Before the details fade, capture what actually happened during the March crunch. Which returns required last-minute scrambles, and why? Which clients delivered documents after your internal cutoff?
A quick internal review while memories are fresh yields insights you won't recover later. Consider gathering your team for 15 minutes to discuss what slowed you down most, which clients need earlier outreach next year, and where effort was duplicated.
The issues that surfaced in March will compound during April if left unaddressed. Look specifically at communication delays, workflow handoffs between preparers and reviewers, and any review bottlenecks that created last-minute pressure. Even small fixes now can meaningfully reduce April stress.
April 15 carries multiple filing obligations beyond individual returns. Here's what you're managing across your client base:
Form 1040 is due April 15 for most individual taxpayers. With the IRS expecting approximately 164 million individual returns in 2026, individual returns represent the primary focus after March 16 passes.
Unlike pass-through entities with March 16 deadlines, calendar-year C corporations file Form 1120 by April 15. This distinction often catches newer practitioners off guard since partnerships and S corps follow a different schedule.
Form 709 applies to clients who made gifts exceeding the annual exclusion. This filing often connects to broader estate planning conversations worth having with your clients during the return delivery meeting.
FinCEN 114 is due April 15 for clients with foreign financial accounts exceeding $10,000 in aggregate value at any point during the year, with non-willful penalties up to $16,536 per violation. This form is filed separately from the tax return through the BSA E-Filing System, not with the IRS directly.
Retirement contribution deadlines often align with filing deadlines, creating planning opportunities that clients frequently miss.
Prior-year contributions to Traditional and Roth IRAs can be made until April 15. Many clients don't realize they still have time to reduce their tax liability or fund their Roth after seeing their return prepared.
SEP IRA contributions can be made until the extended due date of the tax return, provided an extension is filed. This flexibility significantly affects the advice you give business owner clients. They don't have to decide by April 15 if they're extending.
Employee contributions to a Solo 401(k) were due by December 31 of the tax year. However, employer contributions follow the business return deadline, including extensions. This distinction from SEP IRA rules matters when advising clients on their remaining options.
One of the most misunderstood aspects of the April deadline: an extension provides more time to file, not more time to pay. This distinction trips up clients every year.
Form 4868 secures a six-month extension for individual returns when filed by April 15. The form itself is straightforward, but the key is ensuring clients understand what it does and doesn't cover. Filing the extension is easy. Understanding the payment obligation is where confusion happens.
Form 7004 handles extensions for corporations, partnerships, and trusts. Note that extensions for pass-through entities were due March 16. If those were missed, you're already dealing with potential penalties under IRC Section 6698 (partnerships) or IRC Section 6699 (S corporations).
Failure-to-pay penalties and interest begin accruing after April 15, even with a valid extension. Under IRC Section 6651, the failure-to-pay penalty runs 0.5% per month, while failure-to-file runs 5% per month. Filing the extension dramatically reduces penalty exposure, even without full payment.
April 15 is also the deadline for first-quarter estimated tax payments for the current year. This often gets overlooked while firms focus on completing prior-year returns.
Individuals use Form 1040-ES and corporations use Form 1120-W for Q1 estimated tax payments. Remember: this payment applies to the current tax year, not the return you're filing. Corporate estimated tax rules at the state level add another layer to track. It's easy to conflate the two when you're deep in prior-year work.
Clients who underpaid estimated taxes for the previous year may owe penalties. The safe harbor rules under IRC Section 6654 can help. Paying 100% of prior-year tax (110% for higher earners) typically avoids the penalty regardless of current-year liability.
Calendar-year trusts and estates file Form 1041 by April 15. While often a smaller portion of firm volume, these returns require specialized attention and different expertise than individual returns.
Trusts and estates with gross income of $600 or more, or any taxable income, generally file Form 1041. Grantor trusts may have different reporting requirements depending on how they're structured. The rules vary based on trust type.
Schedule K-1s from Form 1041 flow to beneficiaries for their individual returns. Coordinating this timing prevents downstream delays. A late K-1 from a trust can hold up an otherwise complete 1040, creating frustration for everyone involved.
After March 16, the nature of the work changes, not just the volume. Here's how to manage the transition effectively.
Staff who primarily handled entity returns may shift to individual return preparation and review. Consider skill alignment when making assignments. Someone strong on partnership allocations might not be your best choice for complex individual situations, and vice versa.
Identify which individual clients need immediate outreach. Prioritize those with complex situations, missing documents, or unresolved issues from the prior year. A quick call now prevents a crisis later in April.
K-1s from March 16 filings are critical inputs for many individual returns. Track which K-1s are still outstanding and blocking 1040 completion. If you prepared the entity return, those K-1s are already in hand. K-1s from outside entities often arrive late and create bottlenecks.
The busy season accumulates unanswered research questions. Unresolved questions slow down return completion and increase firm risk.
Triage your research backlog by filing deadline urgency and potential dollar impact. Not every question requires resolution before April 15. Some can wait for extension returns without creating problems.
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The debrief process isn't just about fixing what went wrong. It's about building sustainable practices for future seasons. Firms that document their March 16 lessons and apply them immediately to April workflows consistently report less stress and fewer errors.
Modern research and drafting tools can help your team handle peak periods without adding headcount. When routine research takes minutes instead of hours, you have more time for the high-value advisory work that clients actually appreciate.
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Yes. When April 15 falls on a weekend or a holiday like Emancipation Day in Washington D.C., the deadline shifts to the next business day. This varies by year, so check the calendar each season.
The client benefits from filing their return or an extension by April 15 to avoid the steeper failure-to-file penalty — the maximum combined penalty reaches 47.5% of the tax owed. After filing, they can request an IRS installment agreement using Form 9465 or apply for currently-not-collectible status to manage the debt over time.
The IRS may waive penalties under IRC Section 6654(e) for reasonable cause, but first-time penalty abatement typically applies to filing and payment penalties rather than estimated tax penalties. The safe harbor rules are usually the better path for avoiding estimated tax penalties.
Most states follow the federal deadline, but some have different due dates or their own automatic extension rules. Always verify each state's specific requirements separately. Assumptions here can be costly for both you and your clients.
