Multistate Tax Training for Staff Accountants: Build Nexus, Apportionment, and Filing Judgment

What Is Multistate Tax Training for Staff Accountants?

Multistate tax training is structured development that teaches staff accountants how to identify state connections, distinguish tax types, research nexus, evaluate P.L. 86-272 and other limitations, source receipts, calculate apportionment, determine potential filing obligations, document conclusions, and escalate uncertain or high-risk issues before review.

It should cover more than corporate income-tax calculations. Depending on the client, multistate activity can affect:

• Corporate income and franchise taxes
• Gross-receipts or business-activity taxes
• Sales and use taxes
• Pass-through entity filings
• Nonresident owner withholding
• Composite returns
• State PTE tax elections
• Payroll withholding
• Unemployment taxes
• Local taxes
• Secretary-of-state registrations
• Annual reports and related compliance

A junior accountant does not need to independently resolve every one of those issues. But they do need to recognize when one may exist.

That is the developmental line firms often miss.

Why Multistate Tax Has Become a Staff-Training Problem

Multistate tax used to be easier for many smaller CPA firms to compartmentalize. A client had offices in Florida and Georgia. A distributor owned property in three states. A company hired employees in another jurisdiction. The multistate footprint was visible.

Today, a business can cross state lines without opening another office. It may:

• Hire a remote employee
• Store inventory with a third-party logistics provider
• Sell through a marketplace
• Deliver services remotely
• License software
• Conduct online customer support
• Run digital advertising
• Attend trade shows
• Send technicians into another state
• Exceed an economic threshold
• Acquire a company with an existing state footprint

The tax-return preparer may be the first person in the firm to notice those facts.

A February 2026 Tax Adviser case study was specifically designed to give accounting students and entry-level staff practical experience with state income-tax nexus and apportionment. The authors note that public accounting firms can use this type of case for new-staff training because staff will eventually calculate state taxable income and prepare state returns.

You cannot build multistate judgment through a webinar alone. Staff need cases. They need conflicting facts. They need incomplete client information. They need state research. They need calculations. They need reviewer feedback.

Most importantly, they need to learn which question comes next.

The Seven-Gate Multistate Tax Judgment Model

1. Teach Staff to Identify the Tax Before Discussing Nexus

The first question should not be:

“Does this client have nexus in California?”

The first question should be:

“Nexus for what?”

That distinction is fundamental. A company may have one conclusion for sales tax and a different conclusion for corporate income tax. It might also face a franchise tax, gross-receipts tax, payroll withholding, state unemployment registration, pass-through filing, or nonresident withholding.

2. Sales Tax Nexus Is Not Income Tax Nexus

This is one of the most important distinctions an early-career preparer needs to understand.

The U.S. Supreme Court’s 2018 decision in South Dakota v. Wayfair eliminated the old physical-presence requirement for the sales-tax collection issue before the Court. That changed remote-seller compliance dramatically.

But firms should not train staff to reduce the case to:

“Wayfair means economic nexus applies to everything.”

It does not.

The proper lesson is that a state can potentially establish nexus through economic activity without traditional physical presence, but the applicable standard still depends on the particular state and tax.

AICPA’s current Tax Staff Essentials curriculum makes this distinction explicit: one of its learning outcomes is to distinguish between income-tax and sales-tax nexus.

Staff should compare tax systems separately

The point is not to provide automatic conclusions. It is to teach staff that one client fact may have several different state-tax consequences.

3. Train Staff to Build the Facts Before Researching the Law

Multistate tax research is only as good as the facts being researched. Before asking whether the client has nexus, staff should build a state-contact inventory.

People

• Where do employees physically work?
• Did anyone move during the year?
• Are there remote employees?
• Do owners perform services in other states?
• Do salespeople travel?
• Do technicians install or repair products?
• Do employees attend trade shows?
• Are independent contractors operating in other states?

Property

• Where are offices located?
• Where is equipment located?
• Where are vehicles located?
• Is inventory held outside the home state?
• Is inventory stored by a marketplace or 3PL?
• Does the company lease space?
• Is property temporarily located in another state?

Revenue

• Where are customers located?
• Where are products shipped?
• Where are services delivered?
• Where is the benefit of the service received?
• Are there digital products or subscriptions?
• Are there licenses or royalties?
• Are sales reports available by state?

Activities

• Does the business install products?
• Provide post-sale service?
• Offer online customer support?
• Perform warranty work?
• Collect customer information through website functions?
• Recruit employees by state?
• Conduct demonstrations?
• Use third parties to perform activities?

This is the difference between:

“We have $800,000 of sales in State X.”

and:

“We have $800,000 of sales, one remote employee, inventory at a fulfillment center, and technicians who entered the state six times.”

Those are completely different nexus files.

Chart: Build the State Footprint Before the State Return

A return preparer who never looks beyond the prior-year return can easily miss a changed filing footprint.

4. Physical Presence Still Matters

Economic nexus did not make physical presence irrelevant. It gave states another route to nexus.

Staff should still be trained to spot traditional physical-presence facts such as employees, offices, inventory, equipment, property, installation activity, repair activity, service personnel, and regular travel.

A remote employee is particularly important. The employee may be sitting at a kitchen table. The company may have no formal office there. That does not mean the employee disappears for state-tax purposes.

5. Teach P.L. 86-272 as a Narrow Rule, Not a General Nexus Exemption

P.L. 86-272 is one of the easiest concepts for junior tax staff to overgeneralize.

The federal law can restrict a state’s ability to impose a net income tax when an out-of-state business’s activities fall within its protection.

But P.L. 86-272 does not simply mean:

“Remote sellers do not owe state tax.”

The analysis involves questions such as:

• Is the tax a net income tax?
• Is the company selling tangible personal property?
• Are the in-state activities limited appropriately?
• Are orders accepted outside the state?
• Are the goods shipped or delivered from outside the state?
• Are there additional activities that may exceed the protection?
• How has that state interpreted the statute?

The Multistate Tax Commission revised its P.L. 86-272 statement in 2021 to address activities conducted through the internet. That makes this an especially good training topic because the answer may depend on details that junior staff could otherwise dismiss as operational trivia.

Example

Two companies each ship tangible personal property into State A.

Company One

• No employees
• No inventory
• Sales solicitation only
• Orders approved outside the state
• Goods shipped from outside the state

Company Two

• Same sales activity
• Interactive post-sale support
• Other online customer functions
• Additional in-state business activities

The revenue may look identical. The legal analysis may not be.

That is why state-tax training should start with activities rather than revenue alone.

6. Factor-Presence Nexus: Use Models to Teach the Concept, Not as a 50-State Rule

The Multistate Tax Commission has a model factor-presence nexus standard for business-activity taxes. Its model uses thresholds involving property, payroll, sales, and percentage of total factors.

For example, the MTC model includes $50,000 of property, $50,000 of payroll, $500,000 of sales, or 25% of the applicable total factor.

But that does not mean a junior accountant should copy those numbers into every nexus workpaper.

7. Nexus Comes Before Apportionment

Nexus answers:

Can this jurisdiction require the taxpayer to comply with this tax?

Apportionment answers:

How much of the taxpayer’s income or tax base is assigned to that jurisdiction?

They are connected. They are not the same question.

A simple training sequence

Assume a corporation has $2,000,000 of federal/state-adjusted apportionable income and, after applying the state’s sourcing and apportionment rules, a 12% state apportionment percentage.

$2,000,000 × 12% = $240,000 potentially apportioned to the state.

That computation is not the complete state return. Staff still need to consider state modifications, allocable versus apportionable income, filing group, NOLs, credits, tax rate, minimum taxes, franchise or capital taxes, estimated payments, and prior-year overpayments.

But the preparer should understand what the 12% represents. Otherwise, the software is doing mathematics the accountant cannot explain.

8. Stop Teaching the Three-Factor Formula as Though Every State Still Works the Same Way

Many accountants first encounter state apportionment through the traditional property-payroll-sales framework. That history is useful.

But training has to move beyond:

Property + payroll + sales ÷ three.

Depending on the state, entity, industry, and year, the preparer may encounter:

• Single-sales-factor formulas
• Heavily weighted sales factors
• Traditional three-factor approaches
• Industry-specific formulas
• Alternative apportionment
• Market-based sourcing
• Cost-of-performance concepts
• Throwback
• Throwout
• Combined-reporting considerations

The Federation of Tax Administrators maintains state corporate tax and apportionment resources that firms can incorporate into research protocols.

Staff should learn the vocabulary. They should not assume one formula.

9. Market-Based Sourcing Is a Judgment Problem

Service revenue creates another developmental trap.

A staff accountant sees that employees are located in Florida and assumes Florida is where the revenue belongs. But a state using market-based sourcing may focus instead on where the customer receives the service or benefit.

That sounds simple until the client provides services across multiple locations.

Example A — Local consulting engagement

A Florida consulting firm performs work for a Georgia client exclusively related to the client’s Georgia operation.

Example B — National consulting engagement

The same Florida firm advises a corporation headquartered in Georgia, but its work benefits locations in 18 states.

Example C — Digital service

The client sells a subscription service accessed by customers and employees across numerous states.

“Customer is in Georgia” is no longer enough information.

The staff accountant needs to determine:

• What exactly was sold?
• Who received it?
• Where was the benefit received?
• Does the state prescribe a hierarchy?
• Is reasonable approximation permitted?
• Is there a special industry rule?

That requires research and documentation.

10. Teach Staff the Difference Between Destination Sourcing and Market Sourcing

Those terms are sometimes used casually as if they mean the same thing. They should not be.

For tangible personal property, sourcing frequently follows shipment or destination concepts subject to the specific state’s rules.

For services and intangibles, market-based rules may focus on where the service is delivered, where the customer receives the benefit, or where an intangible is used.

The staff accountant should identify the revenue stream before deciding how to source it.

Revenue-stream worksheet

The goal is to prevent the preparer from applying one sourcing assumption to every dollar of revenue.

11. Throwback and Throwout Rules Should Trigger a Reviewer Question

Another reason nexus and apportionment cannot be taught independently is that the taxpayer’s filing footprint can affect the sales factor.

Some jurisdictions use rules that can alter where receipts are included when the taxpayer is not taxable in the destination jurisdiction.

Staff do not need to become SALT specialists before preparing their first multistate return. But they should know this question exists.

12. Nexus Does Not Automatically Mean Tax Is Due

A company could have nexus and still have no taxable income, loss carryforwards, credits, a minimum tax only, an informational filing, a gross-receipts obligation instead, pass-through reporting requirements, or other state-specific obligations.

Likewise:

Staff should never use the amount due as the test for whether a return belongs in the filing matrix.

13. A State With No Conventional Corporate Income Tax Is Not Automatically a “No Filing” State

Junior preparers sometimes learn which states have conventional individual or corporate income taxes and mentally remove the others from the analysis.

That is dangerous.

States can impose other business taxes, franchise taxes, gross-receipts taxes, registrations, payroll requirements, sales taxes, and entity-level obligations.

“No conventional corporate income tax” should lead to research—not deletion from the workpaper.

14. Remote Employees Need Their Own Multistate Tax Checklist

Distributed workforces make employee location one of the best multistate training scenarios.

For each remote employee, collect:

• Work state
• Home state
• Employer office assignment
• Start date
• Move date
• Temporary vs. permanent status
• Payroll withholding state
• State unemployment setup
• Business activities performed
• Sales activities
• Equipment/property used
• Travel

Employer-level questions

• Does the employee create income/franchise tax nexus?
• Does payroll need registration?
• Does unemployment insurance change?
• Does sales-tax nexus need to be reconsidered?
• Does the employee affect apportionment?
• Does the employee affect P.L. 86-272 analysis?
• Are there local obligations?

This is exactly the kind of scenario that should be practiced before a staff accountant encounters it during deadline week.

15. Third-Party Inventory Is Another High-Value Training Scenario

A client may say:

“We don’t have anything in that state.”

Then the fulfillment report shows inventory stored there.

Staff should be taught to reconcile statements like that against evidence. Possible sources include Amazon or marketplace reports, 3PL statements, warehouse reports, inventory detail, and fulfillment agreements.

This is also where professional skepticism training for junior accountants becomes directly relevant.

The preparer should learn to ask:

“What does the evidence show?”

not simply:

“What did the organizer say?”

16. Build a Multistate Filing Matrix Before Preparing Returns

Every multistate business client should have a controlled filing matrix.

Do not treat this example as a filing conclusion. The point is the structure.

The reviewer should be able to see why the state is on the list, what tax is being considered, what remains open, what research supports the conclusion, and who approved uncertain matters.

That is a review-ready file.

17. The Staff Accountant’s Nexus Memo Should Be Short

Do not teach junior staff to write eight pages when eight sentences will do.

State

Georgia

Tax

Corporate income tax

Facts

One employee worked full-time from Georgia beginning June 1. No inventory or office is maintained in Georgia. Company sells both tangible products and consulting services to Georgia customers.

Rule researched

Current Georgia nexus authority and relevant federal limitation.

Analysis

Employee activity creates a physical-presence issue. The company’s service revenue means P.L. 86-272 cannot simply be applied to the entire business without further analysis.

Conclusion

Potential Georgia corporate filing obligation.

Open item

Determine treatment of mixed revenue streams and effective filing date.

Escalation

Manager review required before registration or return preparation.

That is useful.

“Georgia — yes” is not.

18. Teach Research Discipline, Not Google Discipline

State-tax rules change. Staff need a source hierarchy.

1. State statutes and regulations: Start with the law.
2. State department of revenue: Use current instructions, administrative guidance, rulings, FAQs, publications, and tax notices.
3. Federal authority: Use federal statutes and controlling court decisions when relevant.
4. Multistate Tax Commission: Useful for model rules, P.L. 86-272 guidance, uniformity work, and nexus concepts.
5. Federation of Tax Administrators: Useful for state comparisons and links to tax-administration resources.
6. Trusted professional research systems: Checkpoint, CCH, Bloomberg Tax, BNA, or the firm’s approved system.
7. Secondary professional commentary: Useful for identifying issues and developments—but verify material conclusions against authority.

19. AI Makes Multistate Tax Training More Important, Not Less

AI can help a preparer:

• Identify potential issues
• Summarize research
• Organize state comparisons
• Explain terminology
• Draft research questions
• Build preliminary checklists

It can also confidently:

• Apply an outdated threshold
• Mix sales-tax rules with income-tax rules
• Misstate an effective date
• Apply one state’s rule to another
• Ignore industry exceptions
• Invent citations
• Treat proposed legislation as enacted law

Multistate tax is exactly the kind of environment where polished output can still be dangerous.

That is another reason to connect multistate development to professional skepticism training.

20. A Practical Multistate Training Case

Consider this fictional client.

Northstar Equipment & Technology, Inc.

Northstar is headquartered in Florida. During the year it:

• Sold equipment nationwide
• Added remote consulting services
• Hired an employee in North Carolina
• Stored inventory through a third-party fulfillment provider in Texas
• Sent technicians to Georgia for installations
• Generated substantial sales in California and New York
• Added post-sale online support
• Began selling through a marketplace
• Had prior-year filings only in Florida and Georgia

Do not give a new hire a list of the states in which Northstar must file.

Give them the evidence.

Then require the staff accountant to build the analysis.

Phase 1 — Find the State Contacts

Provide payroll reports, sales-by-customer data, fixed assets, inventory locations, travel expenses, marketplace reports, service contracts, and prior-year return lists.

Require a state-contact matrix.

Phase 2 — Separate the Taxes

For each state, require staff to identify potential:

• Income/franchise exposure
• Gross-receipts exposure
• Sales-tax exposure
• Payroll exposure
• PTE implications if applicable

No conclusions yet. Just identify the questions.

Phase 3 — Research Nexus

Staff research current authority. Require the authority used. Require effective dates. Require them to distinguish physical presence, economic presence, factor presence, and P.L. 86-272 protection.

Phase 4 — Source and Apportion

Provide revenue by stream:

• Equipment
• Installation
• Consulting
• Subscription support

Require staff to determine whether each revenue stream follows the same sourcing method.

That is where the exercise begins developing judgment.

Phase 5 — Prepare the Filing Recommendation

The final deliverable should show state, tax, nexus conclusion, authority, sourcing, filing recommendation, open issues, and reviewer escalation.

Now you are training a tax professional—not a form preparer.

Chart: The Multistate Staff Development Ladder

The error is expecting Level 5 judgment after training only Level 2 data collection.

21. What Staff Accountants Should Own—and What They Should Escalate

Appropriate Staff Ownership

With training and firm-approved procedures, staff may be able to:

• Gather state-contact facts
• Reconcile sales by state
• Reconcile payroll by state
• Identify property locations
• Update the filing matrix
• Research published state rules
• Prepare routine apportionment schedules
• Document current-year changes
• Compare the return with prior-year treatment
• Flag threshold crossings
• Draft preliminary nexus conclusions

Manager or SALT Review

Staff should escalate issues such as:

• Uncertain P.L. 86-272 positions
• Mixed protected and unprotected activities
• Material unfiled prior years
• Voluntary disclosure
• Aggressive sourcing positions
• Alternative apportionment
• Combined reporting
• Complex unitary-business questions
• Major business acquisitions
• Large remote-workforce changes
• Marketplace complications
• Industry-specific rules
• Material gross-receipts exposure
• Conflicting state authority
• Significant nexus uncertainty

Staff development does not mean eliminating review. It means giving reviewers better work to review.

That is the same principle behind reducing review notes in accounting.

22. Stop Measuring Multistate Training by Course Completion

Someone can complete eight hours of SALT CPE and still fail to recognize that client inventory moved into another state.

Completion is not competence.

Better multistate readiness metrics

• Nexus facts identified correctly
• Tax types separated correctly
• Authority quality
• Effective dates verified
• Sales reconciled to books
• Sourcing method supported
• Apportionment recomputed independently
• Open items identified
• Escalation occurred at the right time
• Filing matrix completeness
• Repeated review notes
• Reviewer intervention required

23. A 30-60-90 Day Multistate Tax Training Plan

Days 1–30: Recognition

Teach staff nexus vocabulary, differences between tax types, physical versus economic presence, P.L. 86-272 fundamentals, property/payroll/sales evidence, and research hierarchy.

Use short scenarios. Do not start with return software.

Days 31–60: Application

Introduce actual state authority, sales-by-state reconciliation, property and payroll factors, market sourcing, state-specific differences, and filing matrices.

Require sources.

Days 61–90: Judgment

Use cases with missing facts, conflicting evidence, remote workers, inventory, services, marketplace activity, and prior-year omissions.

Require the preparer to state:

Conclusion. Support. Risk. Escalation.

That is the beginning of professional judgment.

For the broader career-development structure, see Accountant Development Plan: How CPA Firms Build Staff From New Hire to Advisor.

24. Connect Multistate Training to Entity Tax Training

Multistate tax should not exist as an isolated specialty topic. It belongs inside normal entity training.

For an S corporation, multistate questions can affect entity filings, shareholder reporting, PTE elections, nonresident filings, withholding, state modifications, and credits for taxes paid elsewhere.

See S Corporation Tax Training for Staff Accountants.

For partnerships, complexity can expand through entity-level filing, partner residency, nonresident withholding, composite filings, PTE taxes, tiered structures, sourcing, apportionment, and partner-specific consequences.

See Partnership Tax Training for Staff Accountants.

Staff should eventually see these as one tax system rather than unrelated return modules.

25. Connect Multistate Training to Tax Software Training

Tax software should implement a conclusion.

It should not create the conclusion.

A preparer using CCH Axcess, UltraTax, ProConnect, Drake, Lacerte, or another system needs to know:

• Why a state was activated
• Why revenue was sourced there
• Why a factor changed
• Why a diagnostic appeared
• Why a state K-1 exists
• Why a payment is due
• Why a return is not being filed

That is why our approach to CCH Axcess tax training for new staff emphasizes review gates for multistate nexus and apportionment rather than treating the software as the technical authority.

26. How SkillAbility Helps CPA Firms Build Multistate Tax Judgment

A CPA firm cannot scale tax capacity if every state question immediately jumps from a junior preparer to the tax partner.

At the same time, the solution is not giving inexperienced staff unlimited authority to make state-tax conclusions.

The answer is progressive responsibility.

BASE — Technical Execution

• Tax workflow
• Source-document recognition
• Workpaper standards
• Research habits
• Tax software competence
• State-return mechanics
• Review readiness

MAPS — Judgment and Advisory Thinking

• Issue recognition
• Interpretation
• Better client questions
• Multistate implications
• Planning awareness
• Client communication

SUMMIT — Review and Leadership

• Review judgment
• Delegation
• Coaching
• Technical escalation
• Client responsibility
• Practice leadership

Multistate tax provides a perfect example of why that progression matters.

A first-year accountant should not independently solve every state-tax issue. But that accountant should become increasingly capable of bringing the manager:

“Here are the facts, here is the authority, here is my preliminary conclusion, and here is the issue I think needs your review.”

That is leverage. That is development.

And that is how firms scale a tax department without relying entirely on senior hires.

Frequently Asked Questions About Multistate Tax Training

What is multistate tax training for staff accountants?

Multistate tax training teaches staff accountants how to identify state-tax exposure, distinguish tax types, research nexus, evaluate P.L. 86-272, source receipts, calculate apportionment, determine potential filing obligations, prepare supporting workpapers, and escalate uncertain matters before review.

What is nexus in state taxation?

Nexus is the connection between a taxpayer and a jurisdiction that can permit the jurisdiction to impose a particular tax or compliance obligation. The applicable nexus standard depends on the state and the type of tax being analyzed.

What is the difference between nexus and apportionment?

Nexus determines whether a state can potentially require a taxpayer to comply with a tax. Apportionment determines how much of a multistate taxpayer’s income or tax base is assigned to that state under the applicable rules.

Is sales-tax nexus the same as income-tax nexus?

No. Sales and use tax, corporate income tax, franchise tax, gross-receipts taxes, payroll taxes, and other state taxes can use different nexus standards. Staff accountants should identify the tax before reaching a nexus conclusion.

Did Wayfair eliminate the physical-presence requirement for every state tax?

No. South Dakota v. Wayfair addressed sales-tax collection and eliminated the physical-presence rule at issue there. States have also expanded economic-presence concepts in other tax systems, but income-tax and other nexus rules must still be researched separately.

What is P.L. 86-272?

P.L. 86-272 is a federal limitation that can protect certain interstate sellers of tangible personal property from state net income taxation when their in-state activities stay within the statute’s protections. It is not a general exemption from sales tax, payroll tax, franchise tax, gross-receipts taxes, or every state filing obligation.

Does a remote employee create state tax nexus?

A remote employee is a significant physical-presence fact and can create state-tax obligations, but the exact consequences depend on the state and tax involved. Firms should separately analyze income/franchise, payroll, unemployment, sales/use tax, and other relevant obligations.

Can inventory held by Amazon or another fulfillment provider create nexus?

Inventory stored in a state can be a significant physical-presence fact. Staff accountants should obtain marketplace and third-party fulfillment reports rather than relying only on the client’s office locations.

What is market-based sourcing?

Market-based sourcing generally assigns receipts from services or intangibles by reference to the customer’s market, such as where a service is received or its benefit is obtained, rather than simply where the seller’s employees perform the work. Specific rules vary by state.

What is single-sales-factor apportionment?

Single-sales-factor apportionment uses only the sales or receipts factor to determine the apportionment percentage instead of combining property, payroll, and sales. State formulas vary, so preparers should confirm the applicable rule for the state, industry, and tax year.

What is a throwback rule?

A throwback rule can require certain sales of tangible personal property to be assigned back to the origin state when specified destination-state taxation requirements are not met. Exact rules vary and should be researched before a preparer changes sourcing.

How often should a CPA firm review client nexus?

At minimum, the multistate footprint should be reconsidered each tax year and whenever material business facts change, including new employees, warehouses, inventory locations, acquisitions, marketplace sales, service offerings, or major sales expansion.

What should a nexus workpaper include?

A good nexus workpaper should identify the state, tax, relevant facts, applicable authority, effective date, analysis, preliminary conclusion, filing recommendation, unresolved questions, and reviewer approval for material judgment calls.

Should junior accountants make nexus decisions?

Junior staff can be trained to gather facts, research routine rules, prepare calculations, and draft preliminary conclusions. Material uncertainty, P.L. 86-272 issues, prior-year exposure, voluntary disclosure, combined reporting, alternative apportionment, and other complex issues should follow the firm’s escalation policy.

Can AI perform multistate nexus analysis?

AI can help identify questions, organize information, and accelerate research, but it should not replace verification against current state and federal authority. Multistate rules change frequently and can depend on effective dates, tax types, industries, and factual details.

How should CPA firms train staff on nexus and apportionment?

Use realistic cases rather than lecture alone. Give staff payroll, sales, inventory, travel, contracts, prior-year returns, and other evidence. Require them to identify state contacts, separate taxes, research current authority, calculate apportionment, prepare a filing matrix, and document what requires reviewer approval.

External Research and Authority Sources

• Multistate Tax Commission — Factor Presence Nexus Standard for Business Activity Taxes
• Multistate Tax Commission — Statement Concerning P.L. 86-272
• Federation of Tax Administrators — State Tax and Apportionment Resources
• AICPA & CIMA — Tax Staff Essentials Level 2
• The Tax Adviser — Multistate Corporate Income Taxes: An Exercise in Nexus and Apportionment
• U.S. Supreme Court — South Dakota v. Wayfair, Inc.

Always verify current state authority and effective dates before relying on a state-tax conclusion.

The Bottom Line

Multistate tax training fails when it becomes a memorization exercise.

There are too many states. Too many taxes. Too many sourcing methods. Too many exceptions. And the rules change.

The better objective is to teach staff a repeatable way to think:

• Identify the tax.
• Build the facts.
• Determine nexus.
• Test the limitations.
• Source the activity.
• Determine the filing obligation.
• Document the conclusion.
• Escalate what exceeds your authority.

That framework gives staff something far more valuable than a list of economic nexus thresholds.

It gives them judgment.

A developing tax accountant should not be expected to independently resolve every difficult multistate issue. But they should know enough to recognize the issue before the reviewer discovers it.

They should know where to research it. They should know how to support their work. And they should know when the answer is:

“I found something we need to look at.”

That is what review readiness looks like.

Train the recognition.
Train the research.
Train the calculation.
Train the judgment.
Then train the advisor.

Protect knowledge. Develop people. Scale the firm.

To building tax staff who can see the issue before review has to find it,

Vincent Howard, CPA
Managing Partner, Howard, Howard and Hodges
SkillAbility for Accounting Firms

© 2026 SkillAbility for Accounting Firms. This article provides general educational information and does not replace tax, accounting, legal, payroll, registration, or other qualified professional advice. Multistate rules, thresholds, sourcing methods, filing requirements, administrative positions, and effective dates can change. Apply current authority to the taxpayer’s actual facts before making or implementing a filing position.