Standard Industrial Classification (SIC) Manual

The Standard Industrial Classification (SIC) Manual is the regulatory taxonomy used by the Oklahoma Tax Commission to determine a business establishment’s eligibility for research and development incentives based on its primary economic activity. Within the Oklahoma R&D tax framework, these four-digit codes serve as the statutory gatekeeper for qualifying high-technology and scientific entities for investment and employment-based credits.

The utilization of the Standard Industrial Classification (SIC) Manual by the Oklahoma Tax Commission (OTC) represents a foundational pillar of the state’s industrial policy, specifically designed to funnel capital and employment incentives toward sectors deemed critical for long-term economic diversification. While the federal government transitioned to the North American Industry Classification System (NAICS) in 1997, the Oklahoma Statutes—most notably Title 68—frequently retain the 1987 SIC Manual as the definitive reference for defining “manufacturing,” “processing,” and “research and development” activities. This statutory persistence creates a specialized regulatory environment where the precise four-digit industry number assigned to an establishment determines its access to significant tax liability reductions, often bifurcating eligibility between general commercial services and high-value innovation activities.

Theoretical and Statutory Foundations of the SIC Manual in Oklahoma

The Standard Industrial Classification system was originally promulgated by the federal Office of Management and Budget (OMB) to facilitate the collection, presentation, and analysis of data describing the structure of the American economy. Its primary function is the classification of “establishments,” which are defined as single physical locations where business is conducted or where services or industrial operations are performed. In Oklahoma, this establishment-based focus is critical because tax credits are often tied to specific facilities rather than the entire corporate entity.

The 1987 revision of the SIC Manual was the first major update since the early 1970s, incorporating changes to reflect the expansion of the service sector and technological advancements in the computing and aerospace industries. For Oklahoma’s R&D tax landscape, the manual serves as a descriptive and prescriptive guide. It provides the legal definitions that distinguish a “qualifying computer services entity” from a general “service organization” (such as a laundry or a repair shop), the latter of which is explicitly disqualified from major industrial credits.

The Hierarchical Structure of Industrial Classification

The SIC Manual is organized into a nested hierarchy that allows state revenue officers to apply increasingly granular tests to a taxpayer’s activities. This structure begins with broad “Divisions” and culminates in “Industry Numbers”.

Level	Identification	Application to Oklahoma R&D Law
Division	A single letter (e.g., Division D)	Identifies broad qualifying sectors like Manufacturing, which is required for the $40 million high-investment tier under 68 O.S. § 2357.4(B).
Major Group	Two digits (e.g., 87)	Groups related activities such as “Engineering, Accounting, Research, and Management Services”.
Industry Group	Three digits (e.g., 873)	Narrows focus to specific categories like “Research and Testing Services”.
Industry Number	Four digits (e.g., 8731)	The precise statutory requirement for the R&D New Jobs Credit under OAC 710:50-15-105.

Oklahoma’s reliance on this hierarchy ensures that tax incentives are not diluted by overly broad interpretations of what constitutes research. By requiring an entity to be “primarily engaged” in specific Industry Numbers, the law prevents companies that perform incidental R&D—such as a retail chain developing an internal inventory app—from claiming credits intended for pure-play technology and scientific firms.

Statutory Framework: 68 O.S. § 2357.4 and the SIC Context

The primary engine for industrial incentives in Oklahoma is Section 2357.4 of Title 68, commonly referred to as the Investment/New Jobs Credit. This statute provides a tiered approach to credits, where the SIC Manual is used to determine if a taxpayer qualifies for a higher “tier” of benefits.

Subsection A: General Manufacturing and Web Portals

Under Subsection A, a credit is allowed for investments in property used in a “manufacturing operation” or a “web search portal establishment”. While this subsection relies partially on general definitions found in 68 O.S. § 1352 (the sales tax manufacturing exemption), the SIC Manual provides the contextual backdrop for what qualifies as a “manufacturing facility”. Qualifying entities under this tier receive a credit equal to the greater of 1% of the cost of qualified depreciable property or $500 per new employee.

Subsection B: The High-Investment Threshold and SIC Division D

Subsection B introduces a significantly more lucrative credit for businesses making massive capital commitments. To qualify for this 2% investment credit or $1,000 per new employee credit, the business must invest at least $40,000,000 within a three-year window. However, capital investment alone is insufficient; the property must be used in the manufacture of products described by any Industry Number contained in Division D of Part I of the Standard Industrial Classification (SIC) Manual.

This specific reference to Division D—which covers “Manufacturing”—is a deliberate policy choice to incentivize the physical production of goods. For R&D companies, this means that those engaged in “Commercial Physical and Biological Research” (SIC 8731) might not qualify for the high-investment tier of § 2357.4 unless they are also engaged in the actual manufacturing of the products they research, as SIC 8731 is located in Division I (Services) rather than Division D.

Quantitative Credit Parameters under § 2357.4

The interplay between investment amounts and employment counts is governed by the following parameters:

Metric	Subsection A Requirement	Subsection B Requirement
Minimum Investment	$50,000	$40,000,000
Investment Credit Rate	1% annually for 5 years	2% annually for 5 years
New Jobs Credit Rate	$500 per FTE	$1,000 per FTE
Industry Restriction	General Manufacturing/Web Portal	Division D of SIC Manual
Carryover Duration	15 years beyond initial 5-year claim	15 years beyond initial 5-year claim

Specific R&D Credit Provisions: OAC 710:50-15-105

While § 2357.4 covers general industrial R&D, the Oklahoma Administrative Code (OAC) § 710:50-15-105 historically provided a dedicated credit for computer services, data processing, and research and development. This regulation explicitly uses the SIC Manual to define the eligible “universe” of companies.

Qualifying SIC Codes for R&D Entities

The credit under 710:50-15-105 is strictly limited to establishments primarily engaged in the following SIC Industry Numbers:

1. Industrial Group 737 (Computer Programming, Data Processing, and Other Computer Related Services):
   • 7372: Prepackaged Software (design, development, and production).
   • 7373: Computer Integrated Systems Design.
   • 7374: Computer Processing and Data Preparation and Processing.
   • 7375: Information Retrieval Services.
2. Industrial Group 873 (Research, Development, and Testing Services):
   • 8731: Commercial Physical and Biological Research.
   • 8732: Commercial Economic, Sociological, and Educational Research.
   • 8733: Noncommercial Research Organizations.
   • 8734: Testing Laboratories.

To qualify as “primarily engaged,” the entity must derive the majority of its business activity or revenue from these classifications. Furthermore, for computer processing (SIC 7374), a specific capital threshold is introduced: the entity must have a minimum of $100,000 in purchases of computers, data processing equipment, or related peripherals.

The Out-of-State Revenue Requirement

A critical hurdle for R&D companies in Oklahoma is the 50% revenue test. All qualified entities must derive at least 50% of their annual gross revenues from sales to out-of-state buyers or consumers. This requirement is intended to incentivize “export-oriented” research—innovation that brings outside capital into the state of Oklahoma.

The law provides a notable exception for federal contracts: all sales to the federal government are legally considered sales to an out-of-state buyer for the purposes of this 50% calculation. This is a vital provision for aerospace and defense R&D firms in the Oklahoma City and Tulsa areas, which may have significant local operations but derive their primary revenue from federal defense spending.

Local Revenue Office Guidance and the Affidavit Process

The Oklahoma Tax Commission (OTC) maintains strict administrative control over the claiming of R&D-related credits through a combination of mandatory annual filings and evidentiary requirements.

Annual Affidavit and Form 563

Entities claiming the Research and Development New Jobs Credit must annually file a sworn affidavit with the OTC. This affidavit is not a mere formality; it serves as a legal attestation that the business continues to meet the SIC-based primary engagement test and the 50% out-of-state revenue threshold.

Accompanying the tax return is Form 563: Research and Development New Jobs Credit. This form requires the taxpayer to:

• Identify the exact Standard Industrial Classification Code (SIC) for the establishment.
• Provide a full explanation of the type of industry in which the business is engaged.
• Furnish the exact location of the facility.
• Maintain a list of all qualified full-time-equivalent (FTE) employees earning at least $35,000 per year.

Employee Qualification and “Support Personnel”

OTC guidance provides a narrow definition of who counts as an “R&D employee” for the credit. Only those actually engaged in computer services, data processing, research and development, or the “support thereof” may be included in the calculation. The Commission explicitly excludes personnel in the following roles, as they are not deemed integral to the research activity itself:

• Administrative and legal staff.
• Accounting and clerical workers.
• Sales and delivery personnel.
• Housekeeping and yard upkeep staff.

This restriction underscores the intent of the law to subsidize “innovation-active” jobs rather than general overhead. If a firm hires 50 new people, but only 20 are software engineers or lab technicians, only those 20 positions generate the $500 per-job credit.

The 2025 Transition: The Oklahoma Research and Development Rebate Program

The landscape of R&D incentives in Oklahoma has entered a period of transition. The legacy income tax credit (OAC 710:50-15-105) was largely repealed or set to sunset for new jobs created after specific windows, leading the legislature to enact Senate Bill 324 (2025).

Mechanism of the SB 324 Rebate

Unlike the previous job-creation credit, which was an income tax credit based on headcount, the new program provides a 5% cash rebate on Qualified Research Expenditures (QREs). The program is administered by the Oklahoma Department of Commerce rather than solely by the Tax Commission.

• Eligibility: Establishments must have qualified research expenditures in Oklahoma and be in good standing with the OTC.
• Definition of QRE: The program adopts the federal definition under Internal Revenue Code Section 41, linking the state rebate to the expenses claimed on federal Form 6765.
• Funding: The program is subject to an annual $20,000,000 fund cap and relies on legislative appropriation.

This shift from SIC-based definitions to federal IRC § 41 standards represents a modernization of Oklahoma’s tax code, aligning state policy with the widely accepted federal “four-part test” for qualified research activities. However, the program’s “first-come, first-served” nature and the requirement for annual legislative funding create a different set of administrative challenges for R&D firms compared to the previous “by-right” income tax credits.

Ad Valorem Exemptions: 68 O.S. § 2902 and SIC Codes

In addition to income tax credits, Oklahoma provides a significant property tax incentive through the Five-Year Ad Valorem Tax Exemption. This exemption applies to “manufacturing facilities” and “research and development facilities”.

Defining R&D Facilities for Property Tax

For the purposes of the ad valorem exemption, a “research and development facility” is typically defined by its relationship to the SIC codes listed in the income tax statutes. Applicants must use Form 900-XM and provide a sworn affidavit to the county assessor’s office.

The OTC oversees the compliance of these applications and requires a Three-Year Affidavit (Form 929-XM) for continued eligibility. Because property tax is a local revenue matter, the County Assessor’s office plays a more active role in the physical inspection of the facility to ensure it matches the SIC-coded activity reported to the state.

Document	Purpose	Agency
Form 900-XM	Initial application for 5-year property tax exemption	County Assessor
Form 900-XM-W	Quality Jobs Wage Compliance Worksheet	OTC Ad Valorem Div
Form 929-XM	3-year affidavit for continued qualification	County Assessor
Form BT-129	Power of Attorney (if signed by non-officer)	OTC

Comprehensive Analysis of Carryover Mechanisms

A unique and strategically important aspect of Oklahoma’s SIC-linked credits is the “unlimited” or “indefinite” carryforward period for capital investment credits under § 2357.4. This creates a long-term “tax asset” for major industrial R&D projects.

The Divergence of Job Credits vs. Investment Credits

The carryover rules differ significantly based on whether the credit was earned through job creation or depreciable property investment:

1. Investment Credits: Unused credits may be carried forward indefinitely. This allows a major manufacturer (SIC Division D) who invests $100 million in a new research and manufacturing hub to utilize the resulting millions in tax credits over several decades as they scale up profitability.
2. Job Creation Credits: Unused credits may be carried forward for 15 years beyond the initial five-year period in which they were established.

This divergence has led to a massive buildup of unused credits on the state’s books. As of Tax Year 2022, the state recorded over $280 million in unused credits carried forward from prior years. The Incentive Evaluation Commission has noted that this creates a “significant vulnerability” for the State’s revenue projections, as these credits—linked to the 1987 SIC definitions—can be “revived” by a taxpayer in any year they generate Oklahoma taxable income.

Economic Evaluation of the SIC-Based Credit Framework

The Oklahoma Incentive Evaluation Commission periodically reviews these programs to determine their return on investment. The findings suggest that while the credits successfully attract large capital projects, their efficacy as a “strategic tool” for innovation is mixed.

Utilization and Market Relevance

The Commission has observed that the $500 per-job credit, based on the 1987 SIC definitions, has not kept pace with inflation. Furthermore, many firms are opting for the Quality Jobs Program instead, as it provides a quarterly cash rebate rather than an income tax credit that must be carried forward.

Program Metric	Investment/New Jobs Credit (§ 2357.4)	Quality Jobs Program
Benefit Type	Income Tax Credit	Cash Rebate
Benefit Amount	1-2% of investment or $500-1,000/job	Up to 5% of new payroll
SIC Use	Mandatory for 4-digit classification	Used for sector eligibility
Duration	5-year claim + long carryforward	Up to 10 years

One of the primary recommendations of the 2023 evaluation was to eliminate the job creation component of the Investment/New Jobs Credit for manufacturers, as the low wage threshold of $7,000 creates “essentially no barrier” and fails to incentivize the high-paying R&D roles the state truly desires.

Technical Application Example: “Aerospace Innovations, LLC”

To illustrate the application of these complex rules, consider “Aerospace Innovations, LLC,” a company establishing a new research facility in Tulsa, Oklahoma.

Phase 1: Classification and Qualification

The company develops advanced composite materials for commercial aircraft. Their primary activity falls under SIC 8731: Commercial Physical and Biological Research. Because they also operate a pilot plant for production, they qualify as a “manufacturer” under the broader definitions of 68 O.S. § 1352.

The company decides to invest $15,000,000 in specialized lab equipment and a new testing hangar. Since this investment is less than $40,000,000, they fall under Subsection A of § 2357.4.

Phase 2: Calculating the Credit

The company hires 25 researchers with an average salary of $90,000. Under § 2357.4, they must calculate both the investment and new jobs components to see which is greater:

1. Investment Credit: 1% of $15,000,000 = $150,000 per year for 5 years.
2. New Jobs Credit: 25 employees x $500 = $12,500 per year for 5 years.

The company naturally chooses the Investment Credit of $150,000 annually.

Phase 3: The SIC 8731 Out-of-State Test

Simultaneously, the company looks at OAC 710:50-15-105 for their 25 researchers. Since they are primarily engaged in SIC 8731, they could also qualify for this credit. However, the state prohibits “double-dipping” on the same activity.

The company checks their revenue:

• $4,000,000 from local maintenance contracts.
• $6,000,000 from a NASA contract (Federal).
• Total Revenue: $10,000,000.

Because the $6,000,000 federal revenue is treated as “out-of-state,” the company passes the 50% revenue test ($6M / $10M = 60%).

Phase 4: Filing and Compliance

1. Affidavit: The company’s CEO signs a notarized affidavit stating the business is primarily engaged in SIC 8731 and derives 60% of revenue from out-of-state/federal sources.
2. Form 506: They file Form 506 for the Investment Credit, providing a detailed schedule of the $15M in equipment.
3. Form 563: Even though they chose the investment credit for the “Jobs/Investment” package, they may still track their R&D employees via Form 563 for separate state reporting requirements or carryover tracking.
4. Carryover: If Aerospace Innovations, LLC has no tax liability in Year 1 because of early-stage losses, the $150,000 credit is carried forward indefinitely on the company’s books until they become profitable.

Final Thoughts

The meaning of the Standard Industrial Classification (SIC) Manual in Oklahoma is far more than a statistical grouping; it is a legal framework that defines the boundary between eligible innovation and ineligible commerce. For the R&D sector, the manual provides the precise language—through codes like 8731 and 7372—that allows a taxpayer to bridge the gap between abstract research and concrete tax relief.

Local revenue office guidance consistently reinforces the requirement for establishments to prove their “primary engagement” in these classifications through annual affidavits and rigorous out-of-state revenue tests. While the state’s tax code is beginning to embrace modern rebate models like SB 324 that reference federal IRC § 41, the legacy of the 1987 SIC Manual remains a vital component of the Oklahoma tax landscape, particularly through the massive carried-forward credits that continue to shape the state’s fiscal obligations. For professional practitioners, the strategic application of these codes remains essential for securing the financial incentives that drive Oklahoma’s technological growth and industrial diversification.