The last two weeks before the filing deadline are the worst possible conditions for making tax decisions. Documents are missing, preparers are booked, and the choices that would have lowered your bill expired months earlier. Tax Crunch spends most of every March explaining that a return filed in April is largely a report on decisions already made. The planning window closed on December 31. Starting early is not about neatness. It is about being in a position to act while acting still changes the outcome.
What can you still change before the year ends, and what can’t you?
Nearly every meaningful tax move for the current year has to happen by December 31, with a short list of exceptions that extend to the filing deadline. Knowing which is which is the whole argument for starting in the fall rather than the spring.
Contributions to a traditional or Roth IRA, and to a health savings account, can generally be made up until the April filing deadline and still count for the prior year. SEP-IRA contributions can run to the extended deadline for those who file an extension.
Almost everything else is a December 31 item. Selling losing positions to offset capital gains, making charitable contributions, converting a traditional IRA to a Roth, bunching deductions into a single year to clear the standard deduction, and deferring or accelerating business income all stop working once the calendar turns. If you are harvesting losses, the wash sale rule disallows the loss if you buy a substantially identical security within 30 days before or after the sale, so those trades need room to breathe rather than being crammed into the last week of December.
When are the actual deadlines?
For the 2026 tax year, the fourth quarter estimated tax payment is due January 15, 2027, and individual returns are due April 15, 2027. Confirm the filing date closer to the season, since the IRS shifts it when it lands on a weekend or a District of Columbia holiday.
Documents arrive on their own schedule. Employers must furnish W-2s by January 31. Brokerage 1099 forms typically follow in mid-February, and corrected versions are common. Schedule K-1s from partnerships and S corporations often do not arrive until March or later, which is the single most frequent reason an otherwise organized filer ends up on extension.
An extension using Form 4868 gives you six additional months to file, moving the deadline to mid-October. It does not extend the time to pay. Interest and the failure-to-pay penalty, which runs at 0.5 percent of the unpaid balance per month, start accruing from the original due date regardless.
Why does waiting cost money rather than just causing stress?
Underpayment is the most common avoidable cost. The IRS charges an estimated tax penalty under Section 6654 when too little is paid during the year. You generally avoid it by paying at least 90 percent of the current year’s tax or 100 percent of the prior year’s total, and that safe harbor rises to 110 percent if your prior year adjusted gross income exceeded $150,000. Checking your withholding in October leaves time to adjust a W-4 or increase a January estimate. Discovering the shortfall in April leaves nothing but the penalty.
Filing early also narrows the window for refund fraud, where someone files a fraudulent return using your Social Security number before you file your legitimate one. The IRS offers an Identity Protection PIN to any taxpayer who requests one, which blocks a return filed without it.
Refund timing shifts too. The IRS states that most electronically filed returns with direct deposit are processed in under 21 days, though returns claiming the Earned Income Tax Credit or the Additional Child Tax Credit cannot have refunds released before mid-February under the PATH Act.
What should Bay Area filers watch specifically?
Equity compensation and multi-jurisdiction filings are where San Francisco returns get complicated, and both reward early attention. Incentive stock options can trigger alternative minimum tax in the year of exercise even without a sale, and modeling that before you exercise is the only way to control it. An 83(b) election on restricted stock must be filed with the IRS within 30 days of the grant, a deadline with no extension and no fix once missed.
California adds its own layer. The Franchise Tax Board grants an automatic six-month extension to file without submitting a form, but payment is still due in April. California does not conform to every federal provision, so a move that helps federally can behave differently on the state return.
Business owners in the city have separate calendars. The San Francisco Annual Business Tax return, covering gross receipts and related taxes, is generally due at the end of February, and business registration renewal follows in the spring. Verify current dates with the Office of the Treasurer and Tax Collector, since thresholds and filing requirements have changed several times in recent years.
How does Tax Crunch structure the year instead of the season?
The useful rhythm is quarterly rather than annual. A fall projection estimates the year’s income and tax before there is still time to act. December is for executing whatever that projection recommended. January and February are for gathering documents as they arrive rather than hunting for them in a pile. March is for the return itself, with room to ask questions.
Appointment availability is a practical consideration as well. Preparer calendars compress sharply after the first week of March, and the returns that get squeezed into the final stretch are the ones most likely to go on extension for reasons that had nothing to do with complexity.
Filing on time is the low bar. Paying the right amount, with every election and deduction you were entitled to, requires being in the conversation months earlier. Reach out to Tax Crunch this fall for a year-end projection and walk into the season with the decisions already made.
Preparing Early for Tax Season: Why Beating the Tax Crunch Saves You More Than Time
