U.S. · Tax forms
1120-S K-1 box 13 credits codes.
Every 2025 shareholder credit code, with the form it goes on.
Box 13 of an S corporation Schedule K-1 reports your share of the corporation’s credits, one code per credit. Most are reported on the credit’s own form or directly on Form 3800, Part III, and shareholders whose only sources for a Form 3800 credit are pass-through entities generally do not have to attach the source credit form. Two exceptions: Form 3468 (investment credit) and Form 8864 (biodiesel, renewable diesel and sustainable aviation fuels) are always attached when they apply. Pick a code to see its destination.
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Result
Box 13 credit codes (2025 K-1)
| Box / code | Credit | What it does and where it goes (per the IRS instructions) |
|---|---|---|
| 13 A | Zero-emission nuclear power production credit | Report this amount in Part II of Form 7213, Nuclear Power Production Credit, or on Form 3800, Part III, line 1u. |
| 13 B | Credit for production from advanced nuclear power facilities | Report this amount in Part I of Form 7213, or on Form 3800, Part III, line 1cc. |
| 13 C and D | Low-income housing credit | If section 42(j)(5) applies, the corporation will report your share of the low-income housing credit using code C. If section 42(j)(5) doesn't apply, your share of the credit will be reported using code D. |
| 13 E | Qualified rehabilitation expenditures (rental real estate) | The corporation will report your share of the qualified rehabilitation expenditures and other information you need to complete Form 3468 related to rental real estate activities using code E. |
| 13 F | Other rental real estate credits | The corporation will identify the type of credit and any other information you need to figure these credits from rental real estate activities (other than the low-income housing credit and qualified rehabilitation expenditures). These credits may be limited by the passive activity limitations. |
| 13 G | Other rental credits | The corporation will identify the type of credit and any other information you need to figure these rental credits. These credits may be limited by the passive activity limitations. If the credits are from more than one activity, the corporation will identify the credits from each activity on an attached statement. |
| 13 H | Undistributed capital gains credit | Code H represents taxes paid on undistributed capital gains by a RIC or REIT. Report these taxes on Schedule 3 (Form 1040), Additional Credits and Payments, line 13a. Reduce the basis of your stock by this tax. |
| 13 I | Biofuel producer credit | Report this amount on line 3 of Form 6478, Biofuel Producer Credit, or Form 3800, Part III, line 4c. |
| 13 J | Work opportunity credit | Report this amount on line 3 of Form 5884, Work Opportunity Credit, or Form 3800, Part III, line 4b. |
| 13 K | Disabled access credit | Report this amount on line 7 of Form 8826, Disabled Access Credit, or Form 3800, Part III, line 1e. |
| 13 L | Empowerment zone employment credit | Report this amount on line 3 of Form 8844, Empowerment Zone Employment Credit, or Form 3800, Part III, line 3. |
| 13 M | Credit for increasing research activities | Report this amount on Section C, line 29, of Form 6765, Credit for Increasing Research Activities, or Form 3800, Part III, line 1c, as follows. The S corporation will provide information necessary to determine if it is an eligible small business under section 38(c)(5)(A). |
| 13 N | Credit for employer social security and Medicare taxes | Report this amount on line 5 of Form 8846, Credit for Employer Social Security and Medicare Taxes Paid on Certain Employee Tips, or Form 3800, Part III, line 4f. |
| 13 O | Backup withholding | This is your share of the credit for backup withholding on dividends, interest income, and other types of income. Include this amount in the total you enter on Form 1040 or 1040-SR, line 25c, and attach a copy of your Schedule K-1 to your tax return. |
| 13 P | Unused investment credit from the qualifying advanced coal project credit or qualifying gasification project credit allocated from cooperatives | Report this amount on Form 3468, Part II, line 6. |
| 13 Q | Unused investment credit from the qualifying advanced energy project credit allocated from cooperatives | Report this amount on Form 3468, Part III, line 2. |
| 13 R | Unused investment credit from the advanced manufacturing investment credit allocated from cooperatives | Report this amount on Form 3468, Part IV, line 2. |
| 13 S | Unused investment credit from clean electricity credit allocated from cooperatives | Report this amount on Form 3468, Part V, line 10. |
| 13 T | Unused investment credit from the energy credit allocated from cooperatives | Report this amount on Form 3468, Part VI, line 31. |
| 13 U | Unused investment credit from the rehabilitation credit allocated from cooperatives | Report this amount on Form 3468, Part VII, line 2. |
| 13 V | Advanced manufacturing production credit | Report on Form 7207, Advanced Manufacturing Production Credit, or Form 3800, Part III, line 1b. |
| 13 W | Clean electricity production credit | Report on Form 7211, Clean Electricity Production Credit, or Form 3800, Part III, line 1gg. |
| 13 X | Clean fuel production credit | Report on Form 7218, Clean Fuel Production Credit, or Form 3800, Part III, line 1q. |
| 13 Y | Clean hydrogen production credit | Report this amount on Form 7210, Clean Hydrogen Production Credit, or Form 3800, Part III, line 1g. |
| 13 Z | Orphan drug credit | Report this amount on Form 8820, Orphan Drug Credit, or Form 3800, Part III, line 1h. |
| 13 AA | Enhanced oil recovery credit | Report this amount on Form 8830, Enhanced Oil Recovery Credit, or Form 3800, Part III, line 1t. |
| 13 AB | Renewable electricity production credit | The corporation will provide a statement showing the allocation of the credit for production during the 4-year period beginning on the date the facility was placed in service and for production after that period. Report this amount on Form 8835, Renewable Electricity Production Credit, or Form 3800, Part III, line 1f. |
| 13 AC | Biodiesel, renewable diesel, or sustainable aviation fuels credit | If this credit includes the small agri-biodiesel producer credit or the sustainable aviation fuels credit, the corporation will provide additional information on an attached statement. If no statement is attached, report this amount on Form 8864, line 10. If a statement is attached, see the instructions for Form 8864, line 10. |
| 13 AD | New markets credit | Report this amount on Form 8874, New Markets Credit, or Form 3800, Part III, line 1i. |
| 13 AE | Credit for small employer pension plan startup costs | Report this amount in Form 8881, Credit for Small Employer Pension Plan Startup Costs, Auto-Enrollment, and Military Spouse Retirement Plan, Part I, or on Form 3800, Part III, line 1j. |
| 13 AF | Credit for small employer auto-enrollment | Report this amount in Form 8881, Part II, or on Form 3800, Part III, line 1dd. |
| 13 AG | Credit for military spouse participation | Report this amount in Form 8881, Part III, or on Form 3800, Part III, line 1ee. |
| 13 AH | Credit for employer-provided childcare facilities and services | Report this amount on Form 8882 or Form 3800, Part III, line 1k. |
| 13 AI | Low sulfur diesel fuel production credit | Report this amount on Form 8896, Low Sulfur Diesel Fuel Production Credit, or Form 3800, Part III, line 1m. |
| 13 AJ | Qualified railroad track maintenance credit | Report this amount on Form 8900, Qualified Railroad Track Maintenance Credit, or Form 3800, Part III, line 4g. |
| 13 AK | Credit for oil and gas production from marginal wells | Report this amount on Form 8904, Credit for Oil and Gas Production From Marginal Wells, or Form 3800, Part III, line 1bb. |
| 13 AL | Distilled spirits credit | Report this amount on Form 8906, Distilled Spirits Credit, or Form 3800, Part III, line 1n. |
| 13 AM | Energy efficient home credit | Report this amount on Form 8908, Energy Efficient Home Credit, or Form 3800, Part III, line 1p. |
| 13 AN | Reserved for future use | Reserved for future use in the IRS instructions. |
| 13 AO | Alternative fuel vehicle refueling property credit | Report this amount on Form 8911, Alternative Fuel Vehicle Refueling Property Credit, Part I, or Form 3800, Part III, line 1s. |
| 13 AP | Clean renewable energy bond credit | Report this amount on Form 8912, Credit to Holders of Tax Credit Bonds. |
| 13 AQ | New clean renewable energy bond credit | Report this amount on Form 8912. |
| 13 AR | Qualified energy conservation bond credit | Report this amount on Form 8912. |
| 13 AS | Qualified zone academy bond credit | Report this amount on Form 8912. |
| 13 AT | Qualified school construction bond credit | Report this amount on Form 8912. |
| 13 AU | Build America bond credit | Report this amount on Form 8912. |
| 13 AV | Credit for employer differential wage payments | Report this amount on Form 8932, Credit for Employer Differential Wage Payments, or Form 3800, Part III, line 1w. |
| 13 AW | Carbon oxide sequestration credit | Report this amount on Form 8933, Carbon Oxide Sequestration Credit, or Form 3800, Part III, line 1x. |
| 13 AX | Carbon oxide sequestration credit recapture | The corporation will provide any information you need to figure your recapture tax. Report the carbon oxide sequestration credit recapture amount on Form 8933, Part III, line 8. |
| 13 AY | New clean vehicle credit | Report this amount on Form 8936, Clean Vehicle Credits, Part II, or Form 3800, Part III, line 1y. |
| 13 AZ | Qualified commercial clean vehicle credit | Report this amount on Form 8936, Part V, or Form 3800, Part III, line 1aa. |
| 13 BA | Credit for small employer health insurance premiums | Report this amount on Form 8941, Credit for Small Employer Health Insurance Premiums, or Form 3800, Part III, line 4h. |
| 13 BB | Employer credit for paid family and medical leave | Report on Form 8994, Employer Credit for Paid Family and Medical Leave, or Form 3800, Part III, line 4j. |
| 13 BC | Eligible credits from transferor(s) under section 6418 | On a statement attached to Schedule K-1, the corporation will identify the type of transferred credits and any other information you need to file your tax returns. Report this amount on Form 3800. See the instructions for Form 3800, Parts III and V, for additional information. |
| 13 BD through BG | Reserved for future use | Reserved for future use in the IRS instructions. |
| 13 ZZ | Other credits | On a statement attached to Schedule K-1, the corporation will identify the type of credit and any other information you need to figure credits other than those reported with codes A through BC. Most credits identified by code ZZ will be reported in Form 3800, Part III. Section 6418 transfer election and retained section 48 credit. |
How box 13 works
The instructions point to the List of Codes and then give one entry per code. A credit that is a passive activity credit to you also requires Form 8582-CR. The Form 3800 Tip in the instructions says shareholders whose only sources for a credit listed in Part III of Form 3800 are partnerships, S corporations, estates, trusts and cooperatives are not required to complete the applicable credit form or attach it. They can instead report the amounts directly in Form 3800, Part III, and enter the entity’s EIN in column (c). The exceptions in the instructions are Form 3468 and Form 8864, which must be completed and attached when they apply.
Two codes people confuse
Code E versus box 17 code C. Qualified rehabilitation expenditures for rental real estate are code E in box 13, and those for other property are box 17 code C. They are separate because they follow different passive activity rules, but you combine them for Form 3468. Code O is backup withholding, your share of the credit for backup withholding on dividends, interest income and other payments.
Codes C and D are both the low-income housing credit: code C if section 42(j)(5) applies, code D if it does not. Keep a separate record of the credit from each source so that you can figure recapture if you dispose of stock. Recapture items are in box 17 codes E and F; see the box 17 page.
Code ZZ and transferred credits
Code BC reports eligible credits from transferors under section 6418, with a statement attached to the K-1. Code ZZ covers credits other than those reported with codes A through BC, identified on an attached statement. If the S corporation made a section 6418 transfer election for a section 48, 48C or 48E credit and uses code ZZ for the part it kept, the instructions send you to Form 3800, Part III, line 4a for section 48, line 1d for section 48C and line 1v for section 48E.
Limits of this page
The table paraphrases the first part of each instruction entry, and some entries carry extra conditions (for example statements from the corporation). Read the full entry for any code that applies to you. For distributions and basis see the box 16 page, and for QBI see box 17 code V.
Sources
- Instructions for Schedule K-1 (Form 1120-S) (2025): Box 13, Credits, and the List of Codes, codes A to BC and ZZ. Read November 2, 2026.
IRS instruction pages last reviewed April 30, 2026. Form and line references are those printed in the 2025 forms and instructions and can change.
Frequently asked questions
What is box 13 on a Schedule K-1 (Form 1120-S)?
Box 13 reports the shareholder's share of the corporation's credits, with one code per type of credit.
Do I need to attach the credit form for a box 13 credit?
Generally not if your only sources for a Form 3800, Part III credit are pass-through entities; you can report the amount directly on Form 3800, Part III. You must still complete and attach Form 3468 and Form 8864 when they apply.
What is the difference between box 13 codes C and D?
Both are the low-income housing credit. Code C is used if section 42(j)(5) applies and code D if it does not.
Where is rehabilitation expenditure reported on an S corporation K-1?
Rental real estate rehabilitation expenditures are box 13 code E, and other qualified rehabilitation expenditures are box 17 code C. Combine them for Form 3468.
What is box 13 code ZZ?
Other credits. A statement attached to the K-1 identifies the credit type and any other information you need; most are reported in Form 3800, Part III.
Not tax advice
This page summarizes IRS instructions, mostly written for the people who prepare the form, and is not tax, legal or financial advice. The estate, trust or corporation that issued the K-1, a CPA or an enrolled agent can confirm what a box or code means for your return. Everything runs in your browser; nothing you enter is sent anywhere.