California R&D Tax Credit: How It Differs From the Federal Credit

The California R&D tax credit, which the Franchise Tax Board calls the research credit, starts from the federal credit in IRC 41 and then changes nearly every number: the rates, the base, where the research must happen, how long unused credit lasts and how much of it a company can use in a year. The California research credit form is FTB 3523. Every California rule below comes from the FTB's 2025 instructions for Form FTB 3523, its What's New page or the California Revenue and Taxation Code, checked on September 25, 2026.

California and federal research credits side by side

California's corporate credit is in R&TC 23609 and the personal income tax version, used by individuals and pass-through owners, is in R&TC 17052.12. Both adopt section 41 "except as follows" and then list the changes. For tax years beginning on or after January 1, 2025, California conforms to the Internal Revenue Code as of January 1, 2025, with its own stated differences. The federal rules themselves are in what the R&D tax credit is and how it works.

What counts as a California research expense

California uses the federal definition of qualified research expenses in section 41(b): wages for qualified services, supplies, amounts paid to use computers, and 65% of contract research, or 75% for payments to a qualified research consortium. Three California rules then narrow it:

• California only. Qualified research and basic research include only research conducted in California, and contract research counts only for work performed on your behalf in California.
• No double benefit with a sales tax exemption. Expenses for tangible personal property eligible for the sales and use tax exemption in R&TC 6378 (property used mainly in teleproduction or other postproduction services, and to maintain, repair, measure or test it) are not QREs.
• Some federal add-ons do not apply. California does not adopt the energy research consortium credit, the 100% rate for energy research paid to small businesses, universities and federal laboratories, or the extension and modifications of the federal credit made in 2006.

Basic research has its own rule. A corporation, other than an S corporation, personal holding company or service organization, can claim 24% of cash payments to a qualified university or scientific research organization under a written contract for basic research performed in California, above a base period amount. California defines basic research more broadly than federal law (it includes applied research for the advancement of scientific or engineering knowledge), and biopharmaceutical and biotechnology companies can count payments to certain public university hospitals and qualified cancer centers.

The regular credit: 15% over a California base

The regular credit is 15% of the year's California QREs above a base amount. The base works like the federal one, with California numbers:

1. Fixed-base percentage. The ratio of QREs to gross receipts for at least three tax years from 1984 to 1988, or, for a start-up company, 3% for each of its first five tax years beginning on or after January 1, 1994 with QREs, then a phase-in. It cannot exceed 16%.
2. Average gross receipts. The average for the four prior tax years, but for a business operating inside and outside California only receipts from sales of property delivered or shipped to California customers count. Receipts from services, rents, operating leases, interest, royalties and licenses are left out, and so are throwback sales.
3. Minimum base. The base amount can never be less than 50% of the current year's QREs, for existing and start-up companies alike.

A company with no California gross receipts under those rules can keep the regular credit only by treating itself as a start-up and entering $0 of receipts, which pushes it to the 50% minimum base; the FTB instructions say such a company should elect the simplified credit instead.

The 3% alternative simplified credit (2025 and later)

For tax years beginning on or after January 1, 2025, California adopted the alternative simplified credit (ASC) with lower rates: 3% of QREs above 50% of the average QREs for the three preceding tax years, or 1.3% of current QREs if any one of those years had none. Only California research counts in the three-year average too. The election is made on a timely filed original return for the year it applies to and binds later years unless the FTB consents to a revocation, requested on federal Form 3115 or Form 1128; deemed consent does not apply.

The ASC replaced the alternative incremental credit (AIC), which California repealed for tax years beginning on or after January 1, 2025. Before that, the AIC used rates of 1.49%, 1.98% and 2.48% (R&TC 23609(h)(1)), so a 2024 or earlier California return that used the AIC was figured at those rates. A company that had elected the AIC must elect the regular credit or the ASC on its timely filed original 2025 return; the old election does not default to either.

Form FTB 3523, part by part

Members of a controlled group, or of businesses under common control, compute one credit for the whole group in Part I and enter only their own share, with a statement showing how it was figured. The credit is claimed with credit code 183. A member of a combined reporting group can assign credit to an eligible affiliate in the same group on Form FTB 3544, and assigned credit cannot be reassigned.

S corporations, partnerships and other pass-through owners

S corporations, partnerships, LLCs, estates and trusts complete Form FTB 3523 to compute the credit, attach it to Form 100S, 565, 568 or 541, and report each owner's share on the California Schedule K-1. The owner then claims it on their own FTB 3523. A few rules differ from federal practice:

• S corporations get a third at the entity level. An S corporation computes the credit at 100%, can apply 1/3 of it against its 1.5% entity-level tax (3.5% for a financial S corporation), and passes 100% through to shareholders pro rata. Carryovers from C corporation years were cut to 1/3 at the S election and cannot pass to shareholders.
• Reduced credit percentages. If the entity elects the reduced credit, each owner's share is multiplied by 87.7% for individuals, estates and trusts, 91.16% for corporations, or 98.5% for S corporations. When the entity does not know an owner's type, it reports the unreduced amount and tells the owner to apply the percentage.
• The section 41(g) limit, with no expiration. An owner's credit from a business is limited to the tax on the owner's income from that business, figured with a formula in the instructions. Unlike federal law, the excess carries over until used, and the limit applies again in each later year.
• Disregarded single-member LLCs. Credit from an SMLLC is limited to the difference in the owner's regular tax with and without the LLC's income, and a year with an LLC loss allows no credit that year, only a carryover.

The $5 million cap on business credits, 2024 through 2029

For tax years beginning on or after January 1, 2024 and before January 1, 2030, all business credits together, including carryovers, cannot reduce a taxpayer's tax by more than $5 million a year (R&TC 23036.4). The 2025 FTB 3523 instructions still show the original end date, tax years beginning before January 1, 2027; SB 122, the 2026 budget trailer bill, extended the limit and the election below through tax years beginning before January 1, 2030, as the FTB's What's New page confirms. For a combined reporting group the limit applies to the group as a whole.

Credit blocked by the cap is not lost. It stays a carryover, and its carryover period is extended by the number of years it was blocked. Or the taxpayer can make an irrevocable election on Form FTB 3870, filed with an original, timely return, to receive the blocked amount as a refundable credit: 20% of it in each of five years, starting with the third taxable year after the election year (R&TC 23036.5). The election must cover all credits blocked that year, not part of them; credit that exceeded the tax on its own does not qualify; and an S corporation cannot elect for credits taken at the entity level.

What the credit cannot reduce, and how long it lasts

The research credit cannot reduce the minimum franchise tax, the annual tax paid by partnerships and qualified subchapter S subsidiaries, the alternative minimum tax, the built-in gains tax or the excess net passive income tax. It can reduce regular tax below tentative minimum tax. Credit that exceeds the tax carries over to later years until it is exhausted, applied to the earliest year first, and it can never be carried back. That is the biggest timing difference from the federal credit, which carries back one year and forward 20 under IRC 39.

Section 174 and the deduction reduction in California

California has not conformed to the 2017 federal change that made research and experimental expenditures amortizable for tax years beginning on or after January 1, 2022, so for 2022 through 2024, when federal law required those costs to be capitalized, California's treatment did not follow. What California does keep is the section 280C trade-off: unless the reduced credit is elected, the section 174 deduction (or any other deduction for research expenses or basic research payments) must be reduced by the current year's California credit, with a schedule attached showing which lines were reduced.

How a federal and a California claim differ in practice

1. Two expense pools. Start from the federal QRE schedule, then keep only wages, supplies and contract research for work done in California. Track location by person and by project from the start; California research is the only research that counts.
2. Two sets of gross receipts. The regular method needs California-delivered sales of property for the four prior years, which most accounting systems do not produce on their own.
3. Two method elections. The California ASC election is made on the California return and revoked only with FTB consent, so it deserves the same thought as the federal choice, especially for a company that has little California-delivered revenue.
4. No payroll offset in California. A startup using the federal payroll election still earns a California credit that waits for California income tax, carried over for as long as it takes.
5. A $5 million ceiling. Large claimants should model the cap each year through 2029 and decide, return by return, whether to carry blocked credit or elect the five-year refund on Form FTB 3870.

The R&D tax credit documentation checklist covers the records both claims rely on, and the state R&D tax credits guide compares California with 20 other states. BEG's tax reviews, run by licensed tax professionals at BEG's tax partner, start with the federal credit and also screen for state credits that fit your facts, as described on the Tax Planning page; the federal payroll election is handled through Payroll Credits.

Sources: California FTB, 2025 Instructions for Form FTB 3523, Research Credit; California FTB, What’s New with Tax Forms (updated August 28, 2026); California Revenue and Taxation Code 23609; California Revenue and Taxation Code 17052.12; California Revenue and Taxation Code 23036.4; California Revenue and Taxation Code 23036.5; 26 U.S.C. 41; 26 U.S.C. 39; IRS, Instructions for Form 6765 (Rev. December 2025). California rules checked against ftb.ca.gov and the California code on September 25, 2026. This is general information, not tax advice for your situation. Tax services are provided by licensed tax professionals under a separate engagement agreement. BEG does not provide tax advice.