Disclosure: I co-founded Mitosis Labs, which runs Private SuperIntelligence. This is an adaptation of the original guide written for family offices. This is general information about IRS filing rules, not tax advice.
K-1 tracking is the job of knowing, for every fund, partnership and trust the family owns, which Schedule K-1 is due, when it is due, whether an estimate has arrived and whether the final has. Under IRS rules a partnership must give each partner a K-1 on or before the day its Form 1065 is required to be filed.
The calendar, then the chain
For tax year 2025 (returns filed in 2026), calendar-year partnerships file Form 1065 by March 15 (March 16 in 2026, because the 15th fell on a Sunday). Form 7004 is generally an automatic 6 months, so an extended partnership can send the K-1 in September. Trusts file Form 1041 by April 15, 2026, with a 5½-month Form 7004, and furnish K-1s to beneficiaries on or before the day the trust must file. Individuals who file Form 4868 have until October 15. An extension to file is not an extension to pay.
For 2025 returns the Form 1065 instructions set a $255 late-filing penalty per partner per month, up to 12 months, and a $340 penalty for each K-1 not furnished when due or furnished with wrong information. If the family office runs its own partnerships, those penalties land on entities you manage.
Outside funds send K-1s to holding LLCs and trusts. The family's own partnerships wait on those, then issue K-1s. Trusts wait next. Family members file Form 1040 last. One late fund K-1 can hold up a holding company, two trusts and four individual returns. That chain is an illustration, not a measured case. The Form 1041 instructions describe amended K-1s, which must be given to each beneficiary when an amended return changes their share.
What the tracker has to hold
Most offices start with a spreadsheet. Dedicated K-1 tracking software exists, and many offices already use one. Keep issuer and tax-document contact, receiving entity, form type (1065, 1041, 1120-S), last year's arrival date, estimate received, final received, amendment, Schedule K-3 expected, and downstream returns waiting on it.
AI can watch tax inboxes, match a K-1 to the right row, compare figures with last year and with the estimate, and draft chase mail for a person to send. Your CPA should still review every figure before it goes on a return. Citi Institute's May 2026 report quotes several CIOs who called the tax workload "highly manual and voluminous," and says AI could automate much of it, from data gathering to flagging potential issues. Citi also found that offices keep final decisions with experienced people.
Tax documents carry some of the family's most sensitive information. See the note on AI for CPAs and client confidentiality before you share K-1 data with any AI tool.
Private SuperIntelligence from Mitosis Labs is an AI concierge for family offices, enterprises and private clients. It works across the office's own email, documents and data, answers with citations, and acts within permissions you set, so it can draft every chase email while a person approves what goes out. The provider keeps no copy of the work. Dedicated tools exist, and many offices already use one. PSI is the option when the office wants an assistant that watches the inboxes and PDFs and leaves the filing calls with the controller and the CPA.
Speak with the founders
Private SuperIntelligence takes a limited number of families at a time so every one gets the same standard of service. Book a private call to talk through your office with Alex Morris.
Prakshal Jain (PJ), Co-founder and CTO, Private SuperIntelligence (by Mitosis Labs)
Alexander Morris, Co-founder and CEO, Private SuperIntelligence (by Mitosis Labs)
Originally published at privatesuperintelligence.si.
Sources: IRS Form 1065 instructions 2025 https://www.irs.gov/instructions/i1065 ; IRS Form 1041 instructions 2025 https://www.irs.gov/instructions/i1041 ; IRS Form 7004 https://www.irs.gov/instructions/i7004 ; IRS extension page https://www.irs.gov/forms-pubs/extension-of-time-to-file-your-tax-return ; Citi Institute May 2026 https://www.citigroup.com/rcs/citigpa/storage/public/ai_in_the_family_office.pdf
Piece ID: K1-DEV
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