Brotman Law — multi-state tax compliance attorneys

Complex Tax Issues

Multi-State Tax Compliance
Every State. One Strategy.

Operating across state lines means filing in multiple jurisdictions, each with different rules. We help businesses navigate nexus requirements, income apportionment, and multi-state compliance obligations.

Sam Brotman Sam Brotman, J.D.|Last updated April 2026

Every State Wants a Piece of Your Business. We Make Sure They Only Get What They're Owed.

If your business has employees, customers, property, or sales in multiple states, you likely have tax filing obligations in each of those states. The rules for determining nexus — the connection that gives a state the right to tax you — have expanded dramatically in recent years.

After the Supreme Court's Wayfair decision, economic nexus means even businesses without physical presence in a state may owe sales tax. And income tax nexus rules vary wildly from state to state, creating a compliance maze that catches many businesses off guard.

We help businesses understand where they have obligations, comply efficiently, and defend against state tax agencies that overreach. For a deeper dive, see our state tax representation services.

What We Handle

Multi-State Tax Services

Nexus Analysis

We analyze your business activities in each state to determine where you have income tax, sales tax, and payroll tax nexus — and where you don't.

Income Apportionment

When you owe income tax in multiple states, apportionment formulas determine how much profit each state can tax. We optimize apportionment to minimize your total state tax burden.

Sales Tax Compliance

Post-Wayfair economic nexus means more sales tax obligations than ever. We help you register, collect, and remit in every required jurisdiction.

Voluntary Disclosure

If you've been operating in states without filing, voluntary disclosure agreements can limit back-tax exposure and eliminate penalties.

Multi-State Audit Defense

When a state audits your returns, we represent your business — challenging nexus assertions, apportionment calculations, and proposed assessments.

State Tax Planning

We help structure your operations to minimize total state tax liability through entity selection, operational structuring, and strategic planning.

Understanding the Landscape

Multi-State Tax: Explained

What is nexus and why does it matter?

Nexus is the minimum connection a state requires before it can tax your business. Physical nexus arises from having employees, property, or offices in a state. Economic nexus arises from exceeding sales thresholds — typically $100,000 in sales or 200 transactions — even without physical presence.

After the 2018 Wayfair decision, economic nexus for sales tax applies in nearly every state. Income tax nexus rules vary by state and are still evolving.

How does income apportionment work?

When your business has nexus in multiple states, each state can tax its 'fair share' of your income. Most states use a formula based on sales, payroll, and property in the state relative to your total. Many states have moved to single-sales-factor apportionment, which taxes based only on where your customers are located.

The choice of entity, location of operations, and sales structure can all affect apportionment and your total state tax burden.

What is a voluntary disclosure agreement?

A VDA is an agreement with a state where you come forward to register and begin filing. In exchange, the state typically limits the look-back period (usually 3-4 years) and waives penalties. This is the safest way to cure non-compliance in states where you should have been filing.

We negotiate VDAs on behalf of businesses, often through anonymous pre-clearance processes that protect your identity until terms are agreed.

Do remote employees create nexus?

In most states, yes. Having even one employee working remotely in a state can create income tax, sales tax, and payroll tax nexus. The COVID-era temporary nexus waivers have largely expired, and states are actively enforcing nexus rules against businesses with remote workers.

Why Brotman Law

Multi-State Tax Compliance Made Manageable

50-State Knowledge

We understand nexus rules, apportionment formulas, and filing requirements across all 50 states and the District of Columbia.

Nexus Analysis Expertise

We've conducted nexus analyses for businesses in technology, e-commerce, manufacturing, professional services, and more.

VDA Negotiations

We negotiate voluntary disclosure agreements that minimize back-tax exposure and eliminate penalties.

Audit Defense

When states challenge your returns, we defend your positions on nexus, apportionment, and sourcing across every jurisdiction.

Compliance Systems

We help implement multi-state compliance systems that keep your business current across all filing obligations.

California Foundation

With deep expertise in California tax, we provide particularly strong support for businesses with California connections operating nationwide.

Free Guide

Read our Multistate Tax Guide

A comprehensive, attorney-written resource covering everything you need to know about this topic.

Related services: International Tax  •  International Tax Issues  •  Other State Tax

Also consider: IRS Audits  •  Criminal Tax Defense

Frequently Asked Questions

Multi-State Tax FAQs

How do I know which states I need to file in?

We conduct a comprehensive nexus analysis examining your physical presence, employee locations, sales volumes, and other connection factors in each state. This identifies all current filing obligations and potential exposure for past non-compliance.

What is economic nexus?

Economic nexus means a state can require you to collect sales tax based solely on your sales volume in that state, even without physical presence. Most states set the threshold at $100,000 in sales or 200 transactions per year.

Can I be taxed on the same income by two states?

In theory, apportionment should prevent double taxation — but it doesn't always work perfectly. Credit mechanisms and careful planning can minimize overlap, but some double taxation can occur when states use different apportionment formulas.

What happens if I haven't been filing in a state I should have?

You may have back-tax liability including taxes, penalties, and interest. A voluntary disclosure agreement is typically the best path forward — it limits the look-back period and waives penalties in exchange for coming into compliance.

Do I need to register for sales tax in every state?

Only in states where you have nexus — either physical or economic. We analyze your sales data and determine exactly which states require registration and collection.

How does the Wayfair decision affect my business?

The 2018 South Dakota v. Wayfair decision allows states to impose sales tax collection obligations on out-of-state sellers who meet economic nexus thresholds. If you sell products or taxable services to customers in multiple states, you likely have new collection obligations.

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