Updated October 17, 2026. Quick answer: Box 9a shows a percentage when a total distribution was made to more than one person, and, for a life annuity from a qualified plan or a section 403(b) plan with after-tax contributions, box 9b may show the employee’s total investment in the contract. The recipient instructions say box 9b “is used to compute the taxable part of the distribution” and point to Pub. 575. The payer instructions add that the payer is “not required to enter the total employee contributions or designated Roth contributions in box 9b”.
Retirement forms read line by line: Form 4972 lines 8 to 17 and Form 4972 lines 18 to 30.
What boxes 9a and 9b are
The form prints box 9a as “Your percentage of total” distribution and box 9b as “Total employee contributions”. Both boxes are quoted below from the recipient and payer instructions. The box 1 amount is covered on the box 1 page and the box 2a amount on the box 2a page. The rest of the form is indexed at Form 1099-R boxes explained.
Box 9a: your percentage of a total distribution
The recipient instructions give box 9a a single sentence: “If a total distribution was made to more than one person, the percentage you received is shown.” The phrase “total distribution” has a specific meaning in the payer instructions: “A total distribution is one or more distributions within 1 tax year in which the entire balance of the account is distributed.” The total distribution checkbox in box 2b is covered on the box 2b page.
What the payer is told to enter is just as narrow: “If this is a total distribution and it is made to more than one person, enter the percentage received by the person whose name appears on Form 1099-R.” The next sentence in the payer instructions reads: “You need not complete this box for any IRA distributions or for a direct rollover.” Code G, one of the box 7 codes, is covered on the code G page.
A labelled illustration of what a percentage means
This is an illustration, not an IRS example. Suppose a total distribution was made to two people and your form shows 40% in box 9a. The remainder of the whole would then be 100% minus 40%, which is 60%.
Box 9b: total employee contributions
The recipient instructions describe box 9b this way: “For a life annuity from a qualified plan or from a section 403(b) plan (with after-tax contributions), an amount may be shown for the employee’s total investment in the contract.” The next two sentences read: “It is used to compute the taxable part of the distribution. See Pub. 575.”
The payer instructions say “You are not required to enter the total employee contributions or designated Roth contributions in box 9b.” and then “However, because this information may be helpful to the recipient, you may choose to report them.”
What the payer instructions say about the figure, and box 5
The payer instructions continue: “If you choose to report the total employee contributions or designated Roth contributions, do not include any amounts recovered tax free in prior years.”
They then say: “For a total distribution, report the total employee contributions or designated Roth contributions in box 5 rather than in box 9b.” Box 5 is described on the box 5 page. The recipient instructions describe it as “the employee’s investment in the contract (after-tax contributions), if any, recovered tax free this year”. The box 5 payer instructions repeat the point: “If a total distribution is made, the total employee contributions or insurance premiums available to be recovered tax free must be shown only in box 5.”
The percentage in the box 8 instructions
The recipient instructions for box 8 also mention a percentage: “If the distribution is made to more than one person, the percentage of the annuity contract distributed to you is also shown.” The same recipient paragraph adds: “You’ll need this information if you use the 10-year tax option (Form 4972).” Box 8 itself is covered on the box 8 page.
Where to go next
The box 7 codes are listed on the box 7 codes page. A page on a wrong 1099-R is the page on what to do when a 1099-R is wrong. Related pages are the 20 percent withholding page and the 401(k) withdrawal rules page. The federal withholding box is on the box 4 page, and the state and local boxes are on the boxes 14 to 19 page.
Edition and box numbers
The primary read for this page is the 2025 edition of Form 1099-R, the form received in early 2026 for tax year 2025. The 2026 edition was the one irs.gov served as current on 2026-10-17. The filer instructions for boxes 9a and 9b read the same in both editions, and so does the recipient sentence for box 9b. The box 9a recipient sentence is worded differently in the 2026 form: “Your percentage is shown if a total distribution was made to more than one person.” The 2026 instructions also say “We renumbered box 8 and the percentage box to boxes 8a and 8b.” and the 2026 form prints the captions “Percentage of total dist.” and “Total employee contrib.”. Boxes 9a and 9b keep their numbers. Check the tax year printed on the form you received and use the box numbers on that form.
Common mistakes
- Expecting box 9a on every form. The payer instructions say “You need not complete this box for any IRA distributions or for a direct rollover.”
- Looking in box 9b for the figure on a total distribution. The payer instructions say “For a total distribution, report the total employee contributions or designated Roth contributions in box 5 rather than in box 9b.”
- Treating box 9b as a required entry. The payer instructions say “You are not required to enter the total employee contributions or designated Roth contributions in box 9b.”
Related: 1099-R box 7 codes, 1099-R code G, 20 percent withholding on a pension lump sum, 401(k) withdrawal rules, and what to do when a 1099-R is wrong.
Sources
- Form 1099-R (2025) with Instructions for Recipient: IRS archived PDF (irs.gov)
- Form 1099-R (2026) with Instructions for Recipient: https://www.irs.gov/pub/irs-pdf/f1099r.pdf
- 2025 Instructions for Forms 1099-R and 5498: IRS archived PDF (irs.gov)
- 2026 Instructions for Forms 1099-R and 5498: https://www.irs.gov/pub/irs-pdf/i1099r.pdf
Read from the IRS documents linked above on October 17, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.