Box 13, code M.

1. Attach Form 6765 completed through line 30 and stop there. The S corporation does not file Form 3800 for this credit. Item A, the Section 280C election, is answered on this entity form. The Form 6765 guide covers each section.
2. Enter line 30 on Schedule K, line 13g with code M. A qualified small business making the payroll election reports line 30 reduced by line 36, and claims line 36 on its own Form 941 through Form 8974.
3. Allocate to shareholders pro rata on Schedule K-1, box 13, code M, with a statement if any shareholder needs more than the amount.
4. The shareholder enters the box 13 code M amount on Form 3800, Part III, line 1c (line 4i when both the S corporation and the shareholder are eligible small businesses), with the S corporation EIN in column (c), in column (d) or (e) depending on material participation. The Form 3800 guide and the Form 1040 guide take it from there.
5. Report the expense. For tax years beginning after December 31, 2024, domestic research or experimental expenditures are deducted in the year paid or incurred under Section 174A, or capitalized and amortized over not less than 60 months by election. Foreign research stays under Section 174 and is amortized over 15 years. Amortized amounts are reported on Form 4562, Part VI, with 174A in column (d). Revenue Procedure 2025-28 sets out the transition choices for costs capitalized in 2022 through 2024.

An S corporation amends by filing Form 1120-S with the amended return box checked and issuing corrected Schedules K-1. Each shareholder then amends their own return to claim the credit. A claim on an amended return must identify each business component, the research activities performed on it, and the total qualified wages, supplies, and contract research. The IRS also asks who did the work and what they set out to learn, and treats those two items as optional for now. A completed Form 6765 supplies the totals. Through January 10, 2027 the IRS allows 45 days to perfect a deficient claim before ruling on it. A year generally stays open for a refund claim until three years after its return was filed, or two years after the tax was paid if that is later.

• Instructions for Form 1120-S (2025)
• Form 6765 (Rev. December 2024)
• Instructions for Form 6765 (Rev. December 2025)
• Form 3800 (2025)
• Instructions for Form 3800 (2025)
• Instructions for Form 4562 (2025), Part VI
• IRS: Research credit claims (Section 41) on amended returns, frequently asked questions

• Form 6765Completing Form 6765, the credit form itself.
• Form 3800Where the research credit goes on Form 3800 and how it reaches the return.
• Form 1120C corporations: Schedule J, Section 174A, and Form 1120-X.
• Form 1065Partnerships: Schedule K line 15f, K-1 box 15 code M, and the partner.
• Form 1040Individuals: Schedule 3 line 6a, Schedule C, and Form 1040-X.
• Form 1041Estates and trusts: Schedule G line 2b and K-1 box 13 code I.