{"id":84646,"date":"2026-09-18T08:00:00","date_gmt":"2026-09-18T13:00:00","guid":{"rendered":"https:\/\/taxprocenter.proconnect.intuit.com\/?p=84646"},"modified":"2026-09-14T15:13:11","modified_gmt":"2026-09-14T20:13:11","slug":"key-tax-dates-and-to-do-list-october-2026","status":"publish","type":"post","link":"https:\/\/accountants.intuit.com\/taxprocenter\/tax-law-and-news\/key-tax-dates-and-to-do-list-october-2026\/","title":{"rendered":"Key tax dates and to-do-list: October 2026"},"content":{"rendered":"\n

October is an important month for tax accountants because it centers on the extended<\/a> individual filing deadline of October 15, so the first priority is closing out those returns cleanly. Firms should be running final reviews on all extended 1040s, confirming that estimated payments, K-1 data from pass-through entities, and any late-arriving documents have been reconciled before submission.<\/p>\n\n\n\n

This is also the moment to circle back with clients who still owe information, since missing the 15th<\/a> can trigger penalties and interest that clients will remember at renewal time. Beyond individual returns, calendar-year C-corps and other entities with extended deadlines may also fall in this window depending on the tax year, so firms need a clear tracking system to make sure nothing slips through after the personal-return crunch ends.<\/p>\n\n\n\n

Once the extension deadline passes, October is the natural pivot point toward year-end tax planning. This means reaching out proactively to review your clients’ income, capital gains and losses, retirement contributions, and any major life or business events from the year, so there’s still time to act on Roth conversions, tax-loss harvesting, entity structure changes, equipment purchases, or bunching deductions before December 31. For business clients, this is also a good time to revisit quarterly estimated tax payments (Q3 estimates were due mid-September, and Q4 planning should start now) and to flag any changes in tax law that could affect year-end strategy.<\/p>\n\n\n\n

On the firm-management side, October is a good time to debrief on busy season and extension season while it’s fresh: reviewing workflow bottlenecks<\/a>, staff capacity, and client communication gaps, and starting to plan staffing and technology<\/a> needs for the upcoming tax season. Firms should also begin engagement-letter and pricing<\/a> conversations for the next filing year, update any client organizers or portals, and make sure CPE requirements are on track since many state boards have year-end or biennial deadlines. Finally, this is a natural window to send clients a light-touch newsletter or check-in about upcoming deadlines such as 1099s and W-2s that are due in January; you want your relationships to stay warm heading into the next cycle rather than going quiet until tax season starts again.<\/p>\n\n\n\n

Along the way, be sure to pay attention to these important IRS and compliance deadlines.<\/p>\n\n\n\n

\"\"<\/figure>
\n

2026 Tax Planning Guide<\/h2>\n\n\n\n

Unlock your firm’s potential for 2026 with the Intuit Accountants Tax Planning Guide. Gain essential strategies and insights to master evolving tax laws and deliver exceptional client value. Your roadmap to proactive tax planning starts here\u2014simply fill out the form to access your guide.<\/p>\n\n\n\n

\n
Get the Tax Guide<\/a><\/div>\n<\/div>\n<\/div><\/div>\n\n\n\n

In October<\/a>, it is recommended that you:<\/p>\n\n\n\n