Use this skill when planning corporate tax strategy, claiming R&D credits, managing transfer pricing, or ensuring tax compliance. Triggers on corporate tax, R&D tax credits, transfer pricing, tax compliance, sales tax, VAT, international tax, and any task requiring tax planning or compliance strategy.
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
A direct command skips the review prompt. Inspect the source before running it.
Use this skill when planning corporate tax strategy, claiming R&D credits, managing transfer pricing, or ensuring tax compliance. Triggers on corporate tax, R&D tax credits, transfer pricing, tax compliance, sales tax, VAT, international tax, and any task requiring tax planning or compliance strategy.
Plan proactively, not reactively - Tax strategy executed before a
transaction or year-end is worth 10x more than cleanup after the fact.
Entity elections, R&D credit documentation, and transfer pricing policies
must be in place before the relevant period ends - they cannot be backdated.
Document everything - The IRS and most tax authorities shift the burden
of proof to the taxpayer. No documentation means no deduction or credit.
R&D activities, business purpose for expenses, and intercompany agreements
must be contemporaneously recorded, not reconstructed during an audit.
R&D credits are systematically underutilized - Fewer than 30% of
eligible companies claim the federal R&D credit. Most qualifying activities
are ordinary engineering work - debugging, prototyping, iterating on
algorithms, designing new features - not just lab research. The credit can
offset payroll taxes for early-stage companies.
Nexus determines obligation - You owe sales tax or VAT only where you
have nexus (a sufficient connection to that jurisdiction). Physical presence
used to be the only trigger; economic nexus rules (typically $100K in sales
or 200 transactions per state) now apply in every US state. Map your nexus
before collection obligations snowball into back-tax liability.
Transfer pricing must be arm's length - When related entities transact
(parent charges subsidiary for IP, services, or goods), the price must be
what unrelated parties would agree to. Failure to document arm's-length
pricing is one of the most common triggers for international tax audits and
can result in double taxation.
Core concepts
Corporate income tax is levied on a corporation's net taxable income.
The US federal corporate rate is 21% (post-2017 Tax Cuts and Jobs Act). State
rates vary from 0% (Wyoming, South Dakota) to over 11% (New Jersey). Taxable
income differs from book income due to depreciation methods, timing of
deduction recognition, and credits that directly reduce tax liability (not
just taxable income).
Nexus and permanent establishment (PE) are the thresholds that create a
tax collection or income tax obligation. For US sales tax: physical nexus
(office, employee, warehouse) or economic nexus (revenue or transaction
thresholds). For international income tax: a permanent establishment typically
arises when a company has a fixed place of business or a dependent agent in a
foreign country - triggering that country's corporate income tax.
R&D credit qualification under IRC Section 41 requires four-part test:
(1) qualified purpose - developing a new or improved business component;
(2) technological in nature - relies on hard sciences, engineering, or computer
science; (3) elimination of uncertainty - attempts to eliminate technical
uncertainty; (4) process of experimentation - evaluates alternatives through
modeling, simulation, testing, or trial and error. Qualifying expenditures
include wages, contract research (65% of amounts paid to US contractors), and
supplies consumed in research.
Transfer pricing methods are the IRS/OECD-approved approaches for pricing
intercompany transactions: Comparable Uncontrolled Price (CUP) - compare to
identical third-party transactions; Cost Plus - cost of production plus arm's
length markup; Resale Price - resale price minus appropriate gross margin;
Comparable Profits Method (CPM) / Transactional Net Margin Method (TNMM) -
compare operating margin to comparable companies; Profit Split - allocate
combined profit based on relative contribution. Most mid-market companies use
CPM/TNMM because comparable third-party transactions are hard to find.
Common tasks
Identify R&D credit opportunities
Qualification criteria checklist:
Test
Question to ask
Examples that qualify
Qualified purpose
Are you developing or improving a product, process, software, or formula?
New feature, performance optimization, new algorithm
Technological in nature
Does the work rely on engineering, computer science, or physical sciences?
Backend architecture, ML model design, circuit design
Elimination of uncertainty
Is there technical uncertainty about how to achieve the result?
"We don't know if this approach will scale to 10M requests"
Process of experimentation
Are you testing alternatives, iterating, or running experiments?
A/B testing architecture choices, profiling and tuning
Qualifying expenditures:
Wages - W-2 wages for employees whose time is spent on qualified research. Track time by project. Even partial time qualifies (e.g., 40% of a developer's time on a qualifying project = 40% of their wages).
Contract research - 65% of amounts paid to US-based third-party contractors performing qualified research on your behalf.
Supplies - Materials and supplies consumed in the research process (not capital equipment, which is depreciated separately).
Startup benefit: Companies with less than $5M in gross receipts and fewer than 5 years of revenue can apply up to $500K/year of R&D credits against employer payroll taxes (FICA) - even with no income tax liability. This is often the most valuable tax benefit available to early-stage tech companies.
Documentation to maintain contemporaneously:
Project descriptions explaining the technical uncertainty and experimentation
Time logs or percentage estimates tied to individual employees and projects
Payroll records cross-referenced to project time
Meeting notes, design docs, code commits, and test records as evidence of experimentation
Load references/r-and-d-credits.md for full qualification examples, the
four-part test applied to common software development activities, and credit
calculation walkthrough.
Plan for sales tax and VAT compliance
US sales tax nexus checklist:
Physical nexus triggers (any one creates nexus):
Office, store, or warehouse in the state
Employee, contractor, or sales rep working in the state
Inventory stored in a fulfillment center (including Amazon FBA) in the state
Attending trade shows or conducting in-person sales activities
Economic nexus triggers (post-South Dakota v. Wayfair, 2018):
More than $100,000 in sales to that state in the current or prior year
More than 200 separate transactions to that state in the current or prior year
Note: Alaska, Montana, New Hampshire, Oregon, Delaware have no state sales tax
Action steps once nexus is determined:
Register for a sales tax permit in the state before collecting (collecting without registration is a separate violation)
Determine taxability - software-as-a-service is taxable in some states, exempt in others; consult a tax advisor for your product category
Configure your billing system to collect and remit by state (Stripe Tax, Avalara, TaxJar)
File returns on the schedule required by each state (monthly, quarterly, or annually based on volume)
VAT considerations for EU/UK:
EU VAT OSS (One Stop Shop) allows a single EU registration to cover all 27 EU member states for B2C digital services
UK requires separate VAT registration (threshold: £90,000 in UK sales)
B2B sales within the EU typically use the reverse charge mechanism - buyer accounts for VAT
Digital services sold to EU consumers are taxable at the buyer's country rate, regardless of where the seller is located
Design a transfer pricing strategy
Transfer pricing applies when your company has multiple legal entities transacting with each other (e.g., a US parent licensing IP to an Irish subsidiary, or a US entity receiving management services from a Singapore holding company).
Step 1 - Map intercompany transactions:
List every transaction between related entities: IP licenses, management fees, cost sharing, intercompany loans, goods sales, shared services.
Step 2 - Select a method:
Transaction type
Recommended method
IP licenses / royalties
CUP (if third-party royalty data available) or Profit Split
Services (routine)
Cost Plus with a standard markup (typically 5-15%)
Distribution / resale
Resale Price Method or TNMM
Manufacturing
Cost Plus or TNMM
Loans
Applicable Federal Rate (AFR) as minimum arm's-length rate
Step 3 - Benchmark:
Use databases like Bureau van Dijk Orbis, RoyaltyStat, or ktMINE to find comparable uncontrolled transactions or comparable companies to support your pricing.
Step 4 - Document in a transfer pricing study:
Most countries with transfer pricing rules require contemporaneous documentation. The OECD BEPS framework requires a Master File (group-wide overview) and Local File (entity-specific) for large multinationals.
Common pitfall: Do not set intercompany prices to minimize tax without economic substance. A subsidiary must perform real functions and bear real risks to justify a low-tax allocation of profits. Substance requirements include local employees, decision-making authority, and actual risk management.
Structure international operations tax-efficiently
IP holding structure:
Holding IP in a low-tax jurisdiction (Ireland, Netherlands, Singapore) is legitimate when the entity has genuine substance - employees who manage the IP, make licensing decisions, and bear economic risk. The OECD BEPS Action 5 "nexus approach" requires that tax benefits track to the jurisdiction where R&D is actually performed.
Structuring checklist before expanding internationally:
Determine if a foreign subsidiary or branch is appropriate (subsidiaries limit liability and separate tax; branches flow through to parent)
Assess permanent establishment risk - does a traveling employee or a local contractor create PE in the new country?
Review applicable tax treaty between home country and target country
Determine withholding tax rates on dividends, interest, and royalties between the two jurisdictions
Consult a local tax advisor in the target jurisdiction before entity formation
US-specific: Subpart F and GILTI
US corporations with foreign subsidiaries must include certain categories of passive or easily-shifted income (Subpart F income) in US taxable income currently. The Global Intangible Low-Taxed Income (GILTI) regime taxes US multinationals on excess foreign profits. These rules significantly limit the benefit of parking income in low-tax foreign entities without genuine substance.
Prepare for a tax audit
Types of audits:
Correspondence audit - IRS requests documentation by mail; most common; respond in writing with supporting documents
Office audit - Scheduled meeting at an IRS office; bring all requested records
Field audit - IRS agent comes to your place of business; most serious; retain a tax attorney or CPA immediately
Audit readiness checklist:
Maintain organized records for at least 3 years from filing date (6 years if substantial understatement is possible; indefinitely if fraud is alleged)
Keep a reconciliation between book income and taxable income (M-1 or M-3 schedule)
Retain all source documents: bank statements, invoices, contracts, payroll records, mileage logs
Document business purpose for all deducted expenses
Keep transfer pricing documentation current
Maintain contemporaneous R&D documentation
If selected for audit:
Do not respond to the IRS directly without a tax professional for anything beyond simple correspondence audits
Respond only to what is asked - do not volunteer additional information
Request a 30-day extension if needed to gather documentation
Understand the statute of limitations: IRS generally has 3 years to audit; 6 years if income is understated by >25%; no limit for fraud
Manage quarterly estimated taxes
Corporations and pass-through entities with expected annual tax liability above $500 (individuals) or $500 (corporations) must make quarterly estimated payments or face an underpayment penalty.
Corporate estimated tax schedule (US):
Quarter
Due date
Q1 (Jan-Mar)
April 15
Q2 (Apr-Jun)
June 15
Q3 (Jul-Sep)
September 15
Q4 (Oct-Dec)
December 15
Safe harbor rules to avoid underpayment penalty:
Pay 100% of prior year's tax liability (25% per quarter), OR
Pay 100% of current year's actual liability as you go (annualized income method)
For C-Corps: The safe harbor is 100% of prior year tax. Large corporations (taxable income >$1M in any of the prior 3 years) must use 100% of current year estimates.
Cash flow tip: Use the prior-year safe harbor when this year is expected to be a high-income year. Use the annualized income method when income is weighted toward early quarters and the business slows later in the year.
Optimize entity structure
Entity comparison for US businesses:
Entity
Tax treatment
Key advantage
Key disadvantage
C-Corporation
Double taxation (21% corp + 15-20% dividend)
QSB stock exclusion (QSBS), no income limit for deductions, investor-friendly
Dividends taxed twice; distributions not deductible
S-Corporation
Pass-through (no entity tax)
Avoid self-employment tax on distributions
Limits: 100 shareholders max, US citizens/residents only, one class of stock
LLC (single/multi)
Pass-through by default
Flexible profit allocation, no formality requirements
Self-employment tax on all active income unless S-Corp election made
Partnership
Pass-through
Flexible allocations, step-up in basis on contribution
SE tax, complexity of Schedule K-1
QSBS (Qualified Small Business Stock) - Section 1202:
Shareholders of a C-Corp can exclude up to $10M (or 10x basis, whichever is greater) of gain from federal capital gains tax if the stock was issued when the company had less than $50M in assets and held for more than 5 years. This is the single largest potential tax benefit available to startup founders and early investors. Entity must be a C-Corp at time of issuance - S-Corps and LLCs do not qualify.
Anti-patterns / common mistakes
Mistake
Why it's wrong
What to do instead
Filing taxes without reviewing prior-year elections
Elections like accounting methods, depreciation, or R&D credit elections must often be made with the original return; missed elections are hard to fix
Review all available elections with your CPA before filing; use an extension if needed
Audit all engineering, product, and QA wages; partial-time allocation qualifies
Collecting sales tax without registration
Collecting without a permit is a separate violation; states can assess penalties beyond the tax itself
Register before collecting; consider a VDA (Voluntary Disclosure Agreement) for past exposure
Setting intercompany prices to a round number without benchmarking
Round numbers signal that pricing was set without economic analysis; automatic audit red flag
Support all intercompany prices with a contemporaneous benchmarking study
Missing the S-Corp reasonable salary requirement
S-Corp owners who take no salary to avoid payroll tax face IRS reclassification of distributions as wages
Pay a reasonable salary (market rate for the services performed) before taking distributions
Waiting until December to do tax planning
Year-end planning has limited options; most high-impact strategies (retirement plan setup, equipment purchases, entity elections) require action before December 31
Review tax position quarterly; engage a CPA in Q3 for year-end planning
Gotchas
R&D credits require contemporaneous documentation, not retroactive reconstruction - The IRS can and does reject R&D credit claims where time logs were created after the fact. Time-tracking systems must be running before the tax year you intend to claim. Reconstructed records from Jira or git history alone are not sufficient.
Economic nexus thresholds are based on prior-year activity, not current-year - Many states look at the prior calendar year to determine if the current year creates nexus. A company that crossed $100K in sales to California in 2023 has nexus there starting January 1, 2024 - not the day they crossed the threshold.
QSBS exclusion requires the company to be a C-Corp at issuance - Converting from LLC to C-Corp after investors receive units does not retroactively qualify. The shares must be original-issue C-Corp stock when issued. Advise on entity type before any equity grants.
S-Corp reasonable compensation is not optional - The IRS actively audits S-Corp owner-operators who pay themselves below-market salaries. The standard is what the company would pay a third party to do the same job, not what feels tax-efficient.
Sales tax registration must precede collection - Collecting sales tax before obtaining a state permit is a separate violation from failure to collect. Some states treat collection without registration as fraud. Register before enabling tax collection in billing systems.
References
For detailed content on specific sub-domains, read the relevant file from
references/:
references/r-and-d-credits.md - Full R&D credit qualification guide with
examples mapped to common software development activities, the four-part test
applied to real scenarios, credit calculation methodology, and the startup
payroll tax offset procedure. Load when evaluating or claiming R&D credits.
Only load a references file if the current task requires deep detail on that topic.
Companion check
On first activation of this skill in a conversation: check which companion skills are installed by running ls ~/.claude/skills/ ~/.agent/skills/ ~/.agents/skills/ .claude/skills/ .agent/skills/ .agents/skills/ 2>/dev/null. Compare the results against the recommended_skills field in this file's frontmatter. For any that are missing, mention them once and offer to install:
