CPA client document checklist for the 2027 tax season
For affluent individual clients, the documents that hold up a return are the organizer, a signed engagement letter, W-2s and 1099s, K-1s and proof of estimated payments. Ask for them in a fixed order, tell each client exactly what is missing, and chase on a schedule instead of when someone remembers.
This guide is for independent CPA firms whose individual clients are executives, business owners, real estate investors and partners with K-1s. It covers 2026 returns filed in 2027. It is not tax advice. Check current IRS guidance for your clients.
Want the chase run for you? See Tax Season Ready
When do client documents arrive in the filing season?
Different documents arrive at different times. Chase each one when it should exist, not all in April.
| When | What should be coming | What to do |
|---|---|---|
| January | Organizers and signed engagement letters | Send both early. 15 January is the last 2026 estimated payment date, so ask for payment confirmation in the same message. |
| February | W-2s and most 1099s | Payers generally send these by the end of January or early February. Ask once they are due. |
| March | K-1s from partnerships and S corporations | K-1s are often the last to arrive. Find out early which clients cannot file without one. |
| 15 April 2027 | Filing deadline, or an extension | Decide on extensions in early April, not on the day. |
What should each type of client send?
Every client
- Signed engagement letter and completed organizer.
- W-2s, plus 1099-INT, 1099-DIV and the consolidated brokerage 1099, which includes 1099-B.
- Confirmation of 2026 federal and state estimated payments.
- Any IRS or state notice received since last year's return.
- Charitable gift receipts over $250.
- Mortgage interest and property tax statements.
Executives with equity pay
- RSU, ESPP and stock option statements.
- Forms 3921 and 3922 where they apply.
- Brokerage statements that show cost basis for shares sold.
Business owners
- K-1 and basis information from any S corporation or partnership they own part of.
- Year end payroll records and owner compensation.
Real estate investors
- Income and expenses for each property.
- Closing statements for any purchase or sale during the year.
- Mortgage interest statements, property tax bills and the depreciation schedule from last year.
Partners in LLCs and funds
- K-1s, and any state composite or withholding notices.
- A note of when each K-1 is expected, so you know what is late.
How should you ask, and how often?
Send one message with the exact list for that client. A generic link to the organizer gets a generic response. Name the missing items, link to your own portal, and say who will pick up questions.
Never ask clients to email SSNs or full account numbers. Use your portal.
Three touches is a sensible rhythm: a first request, a reminder to clients who are still missing items, and a final reminder that says a named person will call. In Tax Season Ready the emails go out on day 3, day 7 and day 11 of the chase. The call stays with your firm.
Hi [first name], we are getting ready for the 2026 filing season. To finish your return without an extension we need: [missing items]. Upload them here: [your portal link]. If anything is unclear, reply and [partner] will pick it up.
What do you do about K-1s that arrive late?
Tell the client in March if their return depends on a K-1 that has not arrived. If it is still missing close to the deadline, an extension may be the right call.
Form 4868 extends the time to file an individual return to 15 October. It does not extend the time to pay, so agree an estimated payment before 15 April.
Common objections
"Our portal already sends reminders." Generic reminders go to everyone and say nothing about what is missing. A reminder that names the one outstanding item is the one that gets answered.
"Clients ignore email." Some do. That is what the final reminder and a call from a named person are for. The call is yours to make. A chase should not call your clients for you.
Frequently asked questions
When should I send organizers?
In early January, with the engagement letter. That gives clients time to gather documents before payers start sending W-2s and 1099s.
How many reminders before I call a client?
Two written reminders after the first request, then a call. Three emails in total keeps the pressure steady without turning into noise.
What should clients never email?
SSNs, full account numbers and tax software logins. Ask for uploads through your portal.
Does a late K-1 always mean an extension?
No. If it arrives with time to prepare the return, you file on time. If it does not, an extension to file is common, with an estimated payment made by 15 April.
Next step
If your firm loses weeks every season to chasing documents, Tax Season Ready runs the chase in your firm's name. You approve the wording, no SSNs are collected, and nothing touches your tax software or the IRS. The next trial window is 4 to 15 January 2027, for up to 25 clients at $750. See how the trial works