Cost Accounting Standards — Government Contractor Cost Rules

The Cost Accounting Standards (41 U.S.C. §§ 1501–1506) are a set of 19 mandatory accounting rules that govern how large government contractors measure, assign, and allocate costs to federal contracts. When the government pays a contractor based on cost (cost-reimbursement contracts, time-and-materials contracts, or cost-based pricing of fixed-price contracts), the rules for what counts as a "cost" and how shared costs (like corporate headquarters, R&D, and employee benefits) are allocated across contracts worth billions of dollars directly affect how much taxpayers pay. The Cost Accounting Standards Board (CASB) — an independent board within the Office of Federal Procurement Policy (part of the broader federal procurement framework, closely related to the Contract Disputes Act) — promulgates and amends the standards. CAS applies to contractors with $50+ million in CAS-covered contracts (full CAS coverage) or those with individual contracts over $7.5 million (modified CAS coverage). Virtually all major defense contractors subject to the Federal Acquisition Regulation and many large civilian contractors are subject to CAS.

Current Law (2026)

Legal Authority

• 41 U.S.C. § 1501 — Cost Accounting Standards Board (establishes the CASB as an independent board within OFPP; prescribes its composition and authority to promulgate cost accounting standards)
• 41 U.S.C. § 1502 — Cost accounting standards (CASB must promulgate standards designed to achieve uniformity and consistency in cost accounting practices used by defense contractors and subcontractors)
• 41 U.S.C. § 1503 — Contract price adjustment (if a contractor fails to comply with applicable CAS or fails to follow consistently its disclosed cost accounting practices, the contract price must be adjusted to eliminate increased costs paid by the government)
• 41 U.S.C. § 1504 — Effect on other standards (CAS takes precedence over other cost accounting standards to the extent of any conflict, but does not supersede GAAP for financial reporting purposes)
• 41 U.S.C. § 1505 — Examinations (DCAA and other authorized officials may examine contractor books, records, and accounts to verify CAS compliance)

How It Works

When the government buys a fighter jet or a satellite on a cost-reimbursement contract, it pays the contractor's actual costs plus a fee. The critical question: what counts as a "cost"? A major defense contractor has thousands of employees working simultaneously on dozens of government and commercial contracts. How shared costs — corporate headquarters, IT systems, health insurance, R&D — are allocated across those contracts has billion-dollar implications. CAS provides the rules.

The 19 standards cover specific cost accounting issues: CAS 401 (consistency in estimating, accumulating, and reporting costs), CAS 402 (consistency in allocating costs for the same purpose), CAS 403 (allocation of home office expenses), CAS 405 (accounting for unallowable costs — costs the government refuses to pay, like lobbying, entertainment, and fines), CAS 408 (accounting for compensated personal absence — vacation, sick leave), CAS 409 (depreciation), CAS 410 (allocation of general and administrative expenses), CAS 412 & 413 (pension costs), CAS 414 (cost of money as a cost element), CAS 415 (deferred compensation), CAS 416 (insurance), and others. Each standard addresses a specific area where inconsistent accounting practices could result in the government paying more or less than it should.

Contractors with $50+ million in CAS-covered contract awards receive full coverage — they must comply with all 19 standards and file a CAS Disclosure Statement (CASB DS-2) describing their cost accounting practices in detail: how they accumulate direct and indirect costs, allocate overhead, account for depreciation, handle pension costs, and so on. This disclosure becomes a binding commitment; if the contractor changes its practices without notifying the government, the government is entitled to a contract price adjustment to recover any increased costs. Contractors with CAS-covered contracts of at least $7.5 million but who fall below the $50 million full-coverage trigger receive modified coverage — they need only comply with CAS 401 (consistency in estimating and reporting), CAS 402 (same-purpose consistency), CAS 405 (unallowable costs), and CAS 406 (cost accounting period), plus follow their disclosed practices.

The Defense Contract Audit Agency (DCAA) is the primary CAS compliance auditor. DCAA examines contractor cost accounting systems, reviews Disclosure Statements, audits indirect cost rates, and investigates potential violations. A finding of CAS noncompliance can trigger contract price adjustments, withholding of payments, and — in serious cases — fraud referrals to DOJ. Contractors preparing for DCAA audits should understand that the audit scope covers not just current period costs but prior periods where CAS noncompliance may have persisted, and that inadequate Disclosure Statements are themselves a compliance finding even before a specific cost allocation error is identified.

How It Affects You

If you're a large government contractor with $50+ million in CAS-covered awards: Your company is subject to full CAS coverage — all 19 standards (CAS 401-420) apply, and you must file a CAS Disclosure Statement (CASB DS-2) with the government. The DS-2 is a detailed description of your cost accounting practices: how you define and measure direct costs, how you establish and allocate indirect cost pools (overhead, G&A, fringe), how you handle depreciation, pension costs, and deferred compensation. Once filed, your DS-2 is a binding commitment — you must follow the practices you described.

The standards that generate the most compliance risk:

• CAS 401/402 (consistency): You must apply the same cost accounting practices to estimate, accumulate, and report costs across similar contracts and similar circumstances. Allocating certain costs to government work but not commercial work is the most common source of CAS violations.
• CAS 403 (home office expense allocation): How you distribute corporate headquarters and shared services costs across segments and contracts. For large multi-segment contractors, CAS 403 methodology disputes can involve hundreds of millions of dollars.
• CAS 405 (unallowable costs): The government refuses to pay for lobbying (31 U.S.C. § 1352), entertainment, fines and penalties, and certain executive compensation above thresholds. You must identify and segregate these in your accounting system so they're never billed to the government. Billing unallowable costs can constitute fraud under the False Claims Act.
• CAS 409 (depreciation): Depreciation charges must use service lives based on the contractor's historical experience — not purely tax depreciation rates or financial statement book accounting.
• CAS 412/413 (pension costs): CAS pension cost measurement differs significantly from ASC 715 (GAAP pension accounting). For contractors with defined benefit plans, the CAS calculation can produce very different charges than the financial statement expense.

The contract price adjustment risk: If you change cost accounting practices without following the required notification and approval process, the government is entitled to a contract price adjustment equal to the increased cost resulting from the change (41 U.S.C. § 1503). An undisclosed practice change — discovered by DCAA during an incurred cost audit — can produce multi-million-dollar price adjustments. Any change to a disclosed practice requires formal notification through your Administrative Contracting Officer (ACO) before implementation.

If you're a mid-size contractor with CAS-covered contracts at least $7.5 million but below the $50 million full-coverage trigger: Modified CAS coverage applies — you must comply with CAS 401 (consistency in estimating, accumulating, and reporting costs), CAS 402 (consistency in allocating costs for the same purpose), CAS 405 (accounting for unallowable costs), and CAS 406 (cost accounting period). A full DS-2 Disclosure Statement is not required, but you must maintain consistent cost accounting practices and demonstrate that consistency to DCAA auditors if examined.

The practical risk for mid-size contractors: Violations typically arise from inconsistency between how costs are estimated in proposals and how they're accumulated on awarded contracts. If you estimate overhead as a percentage of direct labor for pricing, accumulate overhead the same way on actual contracts. Document that your practices for government contracts are consistent with your actual cost accounting behavior.

If you're a small business competing for government contracts: You are generally exempt from CAS — the exemption applies to contractors below the $7.5 million individual contract threshold and to SBA-defined small businesses (13 CFR Part 121). This is a meaningful competitive advantage: no DS-2 filing, no CAS-compliant accounting system requirement, no DCAA CAS audits. You still face FAR cost principles (48 CFR Part 31) for cost-reimbursement contracts, but the CAS infrastructure burden doesn't apply.

Monitor your thresholds carefully: Crossing $7.5 million on a single contract or $50 million in annual CAS-covered awards triggers compliance requirements retroactively. Accounting system upgrades, cost pool restructuring, and staff training to support CAS compliance can take 6-12 months — you need to be ready before the contract award.

If you're a defense industry finance, contracts, or accounting professional: CAS compliance is a specialized discipline requiring mastery of both the 19 standards and the DCAA audit process.

The DCAA audit cycle: The Defense Contract Audit Agency audits CAS-covered contractors through several mechanisms: (1) Incurred cost audits — annual reviews of indirect cost rate proposals submitted after fiscal year-end, verifying that actual costs comply with CAS and FAR Part 31; (2) Forward pricing rate audits — review of provisional billing rates and forward pricing rate agreements (FPRAs); (3) CAS compliance audits — targeted reviews when DCAA identifies potential violations. DCAA has statutory access rights to contractor books, records, and accounts (41 U.S.C. § 1505) — audits are not optional.

Incurred cost proposals: You must submit annual incurred cost proposals for each fiscal year to establish actual indirect cost rates and reconcile estimated rates billed during the year with actual costs. Delays produce contract payment withholding. Many contractors are years behind — DCAA's backlog of unaudited incurred cost proposals is a persistent industry problem. Current status of DCAA's audit backlog is published in DCAA's annual report to Congress at dcaa.mil.

If you're a taxpayer: CAS protects you by requiring that costs allocated to government contracts be measured consistently and allocated based on disclosed practices — preventing contractors from shifting costs from commercial work (where they might be absorbed) to cost-reimbursable government work (where they're billed to taxpayers). DCAA estimates that CAS enforcement saves the government hundreds of millions annually by identifying miscalculated indirect rates, unallowable costs billed to contracts, and undisclosed practice changes. CAS compliance is also subject to GAO audit scrutiny at the program level.

State Variations

CAS applies exclusively to federal contracts:

• State and local governments do not use CAS (they use their own cost principles, often based on OMB guidance)
• State procurement offices may reference federal cost principles when administering state contracts with large contractors
• CAS compliance costs are borne by contractors and ultimately reflected in the prices they charge

Implementing Regulations

The CAS Board regulations implementing the statute live at 48 CFR Parts 9903–9904.

48 CFR Part 9903 — Contract Coverage (33 sections — the administrative and threshold framework determining which contractors and contracts are subject to CAS, what the Disclosure Statement requires, and how cost accounting practice changes are governed):

• § 9903.201-1 — CAS applicability thresholds: CAS coverage is determined at the business unit (division/segment) level based on net CAS-covered awards in the preceding period; full CAS coverage (all 19 standards) applies when a business unit receives $50 million or more in CAS-covered prime contracts/subcontracts in its most recent accounting period; modified CAS coverage (CAS 401, 402, 405, and 406 only) applies when an individual contract or subcontract exceeds $7.5 million; CAS exemptions (no coverage) for contracts below $7.5 million, commercial item contracts, contracts with educational institutions using predetermined indirect cost rates, contracts performed outside the United States, and firm-fixed-price contracts awarded on the basis of adequate price competition
• § 9903.201-2 — Types of CAS coverage: the distinction between full and modified coverage has significant practical impact; under full coverage, the contractor must: maintain a CAS Disclosure Statement (CASB DS-2), disclose all cost accounting practices in writing, notify the government before changing practices, prepare cost impact proposals for changes, and allow DCAA audits of CAS compliance; modified coverage requires only the four fundamental consistency standards without the DS-2 and without notification/impact proposal requirements; the "adequate price competition" exemption requires genuine price competition — contracts where only one price was evaluated, or where the low price was significantly below competitors, may not qualify
• § 9903.201-3 — Solicitation disclosure: every solicitation for a contract subject to CAS must include a notice informing offerors whether the contract is expected to be CAS-covered and what type of coverage applies; the offeror must certify in its proposal whether it is currently subject to CAS and whether this contract would trigger CAS for the first time; this pre-award disclosure is essential because CAS compliance costs (accounting system implementation, DS-2 preparation, annual disclosure statement updates) are allowable costs that affect bid pricing
• § 9903.201-4 — Contract clauses: CAS-covered contracts must include specific contract clauses (CAS clause 52.230-2 for full coverage, 52.230-3 for modified coverage, or 52.230-7 for educational institutions); the clause obligates the contractor to comply with all CAS and with any cost accounting practices described in its DS-2; the clause gives the government the right to negotiate price adjustments when the contractor changes accounting practices; without the clause, the government cannot enforce CAS after award
• § 9903.201-5 — Waivers: agency heads may waive CAS requirements for individual contracts when the CAS requirements would be unreasonable or impractical; waivers are rare and require written justification; the waiver authority is not delegable below the agency head level; Congress's intent was that CAS compliance be near-universal among large government contractors, so waiver criteria are narrow
• §§ 9903.201-6–9903.201-7 — Practice changes and cost impact: when a contractor changes a cost accounting practice (either to achieve compliance or voluntarily), it must notify the government 60 days before implementing the change; the Cognizant Federal Agency (typically DCAA's oversight office) reviews the change and prepares a cost impact analysis; the government is entitled to a price adjustment — downward if the change increases costs to the government, upward if it decreases costs — calculated for all outstanding CAS-covered contracts; this ensures that cost accounting changes do not inadvertently transfer costs between government contracts and commercial work

Part 9903's threshold rules are the gateway to one of the most burdensome regulatory compliance programs in government contracting. The $50 million full coverage threshold effectively means every major defense contractor (Boeing, Lockheed Martin, Raytheon, Northrop Grumman, General Dynamics) operates under full CAS. The Disclosure Statement (DS-2) — a standardized document describing the contractor's accounting system — must be updated whenever accounting practices change and is the basis for all DCAA compliance reviews. CAS noncompliance can result in disallowance of costs, mandatory price adjustments on all affected contracts, and in egregious cases, False Claims Act liability. Recent rulemakings: 76 FR 40819 (July 2011) — updated thresholds to reflect inflation adjustment; 57 FR 14153 (April 1992) — major restructuring of Part 9903.

48 CFR Part 9904 — Cost Accounting Standards: the 19 individual standards themselves, organized by standard number. Each standard contains a statement of purpose, definitions, the fundamental requirement, techniques for application, illustrative examples, and any exemptions. Key standards:

• § 9904.401 — Consistency in estimating, accumulating and reporting costs: a contractor's cost accounting practices for proposal pricing must be consistent with its practices for accumulating and reporting actual contract costs — the foundational anti-bid-shopping rule
• § 9904.402 — Consistency in allocating costs for the same purpose: costs incurred for the same purpose (direct vs. indirect, or allocated to one contract type vs. another) must be treated consistently across contracts — prevents cost shifting between government and commercial work
• § 9904.403 — Allocation of home office expenses to segments: establishes three-step methodology for allocating corporate headquarters costs (residual, three-factor formula, and other bases) to business segments; generates the most complex CAS disputes at large multi-segment defense contractors
• § 9904.404 — Capitalization of tangible assets: contractors must have a written policy establishing a minimum dollar amount for capitalizing assets versus expensing; once established, policy must be applied consistently
• § 9904.405 — Accounting for unallowable costs: unallowable costs (entertainment, lobbying, fines, certain executive comp) must be identified and excluded from any billing; costs that are mutually exclusive with allowable costs require proper segregation
• § 9904.406 — Cost accounting period: the contractor's cost accounting year must be consistently applied as the measurement period for cost accumulation; mid-year period changes require CAS-change notification
• § 9904.408 — Accounting for compensated personal absence: vacation, sick leave, and holiday costs must be measured and allocated over the period in which the employee earns the entitlement, not when taken
• § 9904.409 — Depreciation of tangible capital assets: service lives and depreciation methods must be based on the contractor's own historical experience (not just tax lives); consistent application between government and commercial assets is required
• § 9904.410 — Allocation of business unit G&A expenses: G&A costs must be allocated to final cost objectives using a base representing the total activity of the business unit (typically total cost input, value-added, or single element); allocation base selection must reflect a causal/beneficial relationship
• §§ 9904.412–413 — Pension costs: two standards governing cost measurement and period assignment for defined benefit pension plans; CAS pension cost calculation differs significantly from GAAP ASC 715 accounting, creating complex reconciliation work and generating some of the largest CAS disputes
• § 9904.415 — Deferred compensation: present value of deferred compensation awards (restricted stock, SARs, deferred cash) must be measured at the date of award and allocated to cost accounting periods based on the award formula
• § 9904.418 — Allocation of direct and indirect costs: contractors must have a written statement of accounting policies and practices for identifying costs as direct or indirect; each indirect cost pool must have a consistent allocation base with a causal/beneficial relationship to the pool's costs
• § 9904.420 — Accounting for independent research and development costs and bid and proposal costs: IR&D and B&P costs must be accumulated in separate cost pools and allocated to all final cost objectives based on the same base used to allocate G&A expenses

48 CFR Part 9905 — Cost Accounting Standards for Educational Institutions: a parallel set of 4 standards tailored to universities and academic research institutions, which have different cost structures than commercial contractors — indirect cost "facilities and administrative" (F&A) pools, academic-year budgeting, and the 2 CFR Part 200 Appendix III framework for sponsored research:

• § 9905.501 — Consistency in estimating, accumulating and reporting costs: educational institutions' practices for estimating costs in proposal pricing must be consistent with practices used to accumulate and report actual contract costs; the university-specific analog of commercial CAS 401 (§ 9904.401), preventing universities from proposing under one accounting approach and billing under another
• § 9905.502 — Consistency in allocating costs for the same purpose: each type of cost (direct vs. indirect) must be consistently treated across contracts; a university cannot allocate travel as indirect on one sponsored project and as direct on another project of the same type in like circumstances; the same methodology must apply to all final cost objectives for costs incurred in like circumstances
• § 9905.505 — Accounting for unallowable costs: costs that are expressly unallowable under 2 CFR Part 200 Appendix III (alumni relations, lobbying, entertainment) must be identified, segregated, and excluded from any billing or proposal; universities must maintain systems that separately identify unallowable costs even when funded from non-federal sources, because those costs flow into indirect cost pools used to calculate the F&A rates applied to federal awards
• § 9905.506 — Cost accounting period: educational institutions must use their fiscal year as the cost accounting period; if an indirect function exists for only part of a fiscal year, its costs may be allocated to the applicable sub-period only; the fiscal year anchoring ensures consistency in indirect cost rate development and reconciliation across sponsored projects

Part 9905 applies to universities with CAS-covered contracts after 1994. In practice, most major research universities operate under a Negotiated Indirect Cost Rate Agreement (NICRA) using predetermined rates — and universities with predetermined rates are generally exempt from CAS under § 9903.201-1. Part 9905 compliance is most relevant when a university negotiates provisional or billing rates rather than predetermined rates, or when an individual award explicitly includes CAS coverage requirements. The clause for educational institutions is FAR 52.230-7 (rather than 52.230-2 or 52.230-3 used for commercial contractors). Effective date: all four standards effective January 9, 1995; institutions with no prior CAS-covered contracts apply each standard beginning with their next fiscal year after receiving a covered contract.

48 CFR 30.6 — FAR Subpart 30.6: CAS administration in contracts — contract clause requirements, procedures for contractor Disclosure Statements, government review of cost impact proposals when practice changes occur, and remedies for noncompliance. 48 CFR 52.230-1 through 52.230-7 — standard CAS contract clauses incorporated into covered contracts by reference.

Pending Legislation

No standalone CAS reform bills have been introduced in the 119th Congress. Cost accounting standards provisions appear in defense acquisition reform — see Defense Acquisition Reform and Federal Procurement & Contracting.

Recent Developments

The CASB has been relatively inactive in recent years — no new standards have been promulgated since the 1990s, and proposed revisions to existing standards (particularly CAS 412/413 on pension costs) have been slow to finalize. Critics argue that the 19 standards are outdated and don't adequately address modern business practices (cloud computing costs, software development, flexible work arrangements). The interaction between CAS and commercial accounting standards (ASC 606 for revenue recognition, ASC 842 for leases) creates compliance complexity for contractors that must simultaneously satisfy both regimes. DCAA's audit approach has shifted toward risk-based auditing, reducing the burden on contractors with strong internal controls while increasing scrutiny of high-risk areas.