What is the Louisiana R&D tax credit rate?

The rate depends on employer size. As of mid-2026 the structure follows Louisiana's historical tiers: roughly 30% of qualifying incremental research expenditures for companies with fewer than 50 employees, about 10% for companies with 50 to 99 employees, and about 5% for companies with 100 or more. The legislature has adjusted the tiers repeatedly, so verify current rates with the state before relying on them.

How do you claim the Louisiana research credit?

By application to Louisiana Economic Development, not by simply filing a return. LED reviews the application — including support for the qualified research — and issues a certification; the certified credit then goes on the Louisiana return filed with the Department of Revenue. There is an application fee, and claims without certification are invalid.

Is the Louisiana R&D credit refundable?

It has been for the smallest tier in some periods — Louisiana has historically made the credit refundable or convertible for small companies while larger companies carry unused amounts forward. Because the legislature has moved these rules more than once, confirm the current monetization treatment for your size tier with Louisiana Economic Development and the Department of Revenue.

Louisiana's R&D credit: rates that rise as headcount falls

Louisiana's research and development credit inverts the usual assumption that big spenders get the big incentives: the rate rises as the company shrinks. The historical structure — largely intact as of mid-2026 — pays on the order of 30% of qualifying incremental research expenditures for employers with fewer than 50 employees, roughly 10% for employers with 50 to 99, and roughly 5% at 100 employees and up. The credit is also unusual procedurally: nothing goes on a tax return until Louisiana Economic Development (LED) has reviewed an application and certified the credit. The legislature has restructured this program several times; treat the tiers as the design pattern and verify current percentages and eligibility with the state.

The tier structure

The chart shows the historical rate tiers by employer size (as of mid-2026; the legislature adjusts these — verify before relying).

Louisiana R&D credit rate by employee count%

Historical tier structure, largely intact as of mid-2026. Rates apply to qualifying incremental research expenditures; verify current law.

The base is incremental: qualifying Louisiana research expenditures over a base amount derived from prior-year spending, with the qualification concepts borrowed from federal Section 41 — the four-part test and QRE categories — applied to research performed in Louisiana. Companies holding federal SBIR/STTR awards have historically had their own favorable computation keyed to the award amounts. Certain professional-services businesses (accounting, law, medical billing, and similar) have been excluded from eligibility by statute.

Application first, return second

The Louisiana credit is a certified incentive, not a self-assessed one. The taxpayer applies to LED after the close of the year — with an application fee and documentation of the claimed research — and LED issues a certification of the credit amount. Only then does the credit appear on the return filed with the Louisiana Department of Revenue. Application deadlines apply, historically within a fixed window after the year end; a missed window forfeits the year.

This structure has two consequences. First, the state's substantive review happens up front, so documentation standards resemble an audit file: project descriptions, expense support, the increment computation. Second, there is no quiet amended-return route — the certification is the gate.

Monetization, fit, and traps

Monetization has moved over the program's history: in various periods the small-company tier's credit has been refundable or convertible to cash while larger tiers carry forward (Louisiana has used both refundability and multi-year carryforwards, and has adjusted transfer rules). As of mid-2026, plan on the small tier having a cash path and larger tiers carrying forward — but confirm the current rule for your tier before modeling, since this is precisely the kind of detail the legislature likes to revisit. For context on how cash-out provisions compare across states, see refundable and transferable state credits.

The fit is clear from the tiers: Louisiana is most valuable to small companies — a sub-50-employee software or engineering firm earning 30 cents per incremental research dollar is getting one of the strongest state rates in the country, comfortably ahead of high-rate regimes like Rhode Island's. At 100+ employees, 5% of an increment is modest, and the application cost and fee eat into it.

Two traps. First, headcount measurement: the employee-count tiers are cliff-edged, and companies near a boundary should understand how the state counts employees (Louisiana versus everywhere, full-time versus total) before assuming a tier — crossing 50 employees cuts the rate by two-thirds. Second, the application window: unlike the federal credit's generous amended-return lookback, Louisiana's certification deadline is unforgiving, and companies that discover the program two years late have usually lost the early years. The general framework for these state-versus-federal differences is in how state credits differ.