When your independent e-commerce store, AI/SaaS product, game, or short-form content business begins to gain momentum in the U.S. market and orders start pouring in, an unfamiliar challenge often emerges: U.S. tax compliance.
Do any of these questions sound familiar?
“How large must my business be before I’m required to register a company in the United States?”
“I’m receiving orders from dozens of U.S. states. Does that mean I must pay tax in each one?”
“I only sell digital goods or SaaS services. Do I still need to charge sales tax?”
“I’ve heard U.S. tax penalties can be harsh. How do I avoid compliance risks?”
You’re certainly not the only one asking.
At Antom, we recognise that many overseas SMEs don’t have the support of a dedicated compliance team. This guide breaks down, step by step, the essential principles of U.S. tax compliance, helping you navigate requirements with confidence and clarity.
Operating in the United States generally involves two major types of tax:
Understanding the distinction between them is the first step towards compliance.
Physical Product Example
You sell a product for $100 to a customer located in Los Angeles, California.
Calculation:
Nexus is the determining threshold that decides whether you are required to pay tax in a particular state. Once Nexus is triggered, you must register, collect, and file taxes in that state.
There are two main types of Nexus:
They apply differently to Sales Tax and Corporate Income Tax (CIT).
Physical Nexus
Triggered when you have warehouses, inventory, offices, and sales personnel within a state
Only employees directly related to sales activities count; pure customer support or back-office roles generally do not
Physical Nexus
Triggered if you have:
Fixed assets in the state
Any employees (sales, operations, or management)
Economic Nexus
Triggered when state-sourced revenue exceeds statutory thresholds
Example:
California: $610,395
New York: $1,000,000
Not all profits are taxed in that state
Taxable income is allocated using state-mandated apportionment formulas (often a “three-factor formula”)
Once any Nexus condition is met, tax obligations arise, regardless of whether you have registered a U.S. company.
If You Do Not Have a U.S. Company
Even if you operate through a Chinese or other foreign entity:
Register for a sales tax permit
Begin collecting sales tax
File and remit tax on time
2. Income Tax Nexus
Company A:
Texas-registered LLC, no physical presence, annual sales in California exceed $500,000 → CA Sales Tax Economic Nexus
Company B:
New York C-Corp with employees in Illinois → IL Income Tax Physical Nexus
Company C:
Chinese company with no U.S. entity, Washington State SaaS revenue exceeds $300,000 → WA Income Tax Economic Nexus
Many merchants initially enter the U.S. market using overseas entities to keep operations lightweight. This is legally permitted, but it comes with limitations and risks.
Yes. U.S. law does not require foreign companies to set up a U.S. entity to sell. However, once Nexus is triggered, you must register tax accounts and file returns as a Foreign Entity. Many merchants use this approach for early-stage market testing.
Use an overseas entity during early testing. When sales approach state thresholds, plan ahead for U.S. entity registration or engage professional tax agents.
Your company structure affects taxation, fundraising, shareholder eligibility, and compliance costs.
Note: Company structure does not affect Sales Tax Nexus obligations, which are determined by business activity location.
|
Feature Dimension |
LLC (Limited Liability Company) |
C Corp (Corporation) |
S Corp (S Corporation) |
|
Tax Treatment |
Pass-through taxation Profits flow directly to members’ personal tax returns, avoiding double taxation.
|
Double taxation Taxes are paid at the corporate level and again when dividends are distributed to shareholders.
|
Pass-through taxation Similar to an LLC; profits pass directly to shareholders. |
|
Shareholder Eligibility |
No nationality restrictions
|
No nationality restrictions
|
Strict nationality restrictions Up to 100 shareholders; shareholders must be U.S. citizens or tax residents. |
|
Corporate Filing Requirements |
Disregarded Entity (single member)：
Partnership (multiple members)：
|
Form 1120 (U.S. corporation) or 1120-F (foreign corporation) |
Form 1120-S (S Corp return) No federal income tax at the corporate level. |
|
Shareholder Filing Requirements |
Disregarded Entity (single member)：
Partnership (multiple members):
|
When dividends are paid:
|
Shareholders receive Schedule K-1 and report on their individual Form 1040 (U.S. citizens/residents only, 10%–37%). |
|
Formation & Maintenance |
Simple and flexible Low setup and annual maintenance requirements |
Complex and formal Requires board meetings and stricter compliance |
Moderately complex Must meet multiple qualification rules |
|
Best For |
Ideal for international SMEs: optimal tax treatment, liability protection, and no nationality barriers. |
Mature companies planning to raise capital or go public |
Small U.S.-based businesses |
Before final decisions, consult professional tax and legal advisers.
An LLC can later be converted to a C-Corp to support fundraising or listing plans.
Online filing: All states provide electronic systems (e.g. CA CDTFA, NY Tax Online)
With a U.S. company: File using EIN and pay via ACH or credit card
Without a U.S. company:
Register as a Foreign Entity and file using ITIN/EIN
Some states support international payments; due to complexity, local tax agents are recommended
U.S. tax compliance is serious. The best defence is proactive compliance: timely registration, automation tools, complete records, and professional advice.
Late filing penalties: Typically 5%–10% per month, some states double penalties after 2–3 months
Interest: Accrued daily, approx. 3%–6% annually
Civil penalties: Severe violations may incur 50%–100% of unpaid tax as fines
Criminal charges: Fraud, falsified records, or concealed income can affect credit, visas, and immigration status
Platform or bank freezes: Authorities may request platforms such as PayPal or Stripe to withhold funds
This guide is for general informational purposes only and does not constitute legal or tax advice.
U.S. tax laws are complex and subject to change. Always consult a qualified U.S. tax attorney or certified public accountant based on your specific circumstances.