Key Takeaways
- Georgia taxes income by sales, not by where the work happened. If you run a Georgia-based service business with out-of-state customers, market-based sourcing likely shifts more income out of Georgia’s tax base than a cost-of-performance state would.
- There is no throwback rule here. A sale to a state where you have no nexus doesn’t get pulled back into Georgia’s tax base. That’s favorable for companies that sell out of state, though it cuts both ways, more on that below.
- Selling online creates its own exposure, separate from sales tax. Warehousing inventory, crossing a sales threshold, or using a marketplace platform can each create income tax nexus somewhere you never expected to file.
- The sourcing method changes your numbers before you touch a single deduction. Two businesses with identical revenue can owe very different amounts in the same state, depending only on how that state sources the income.
If your business sells into more than one state, Georgia does not tax all of your income. It taxes the share tied to sales made here. That share is set by apportionment, and Georgia calculates it using market-based sourcing, not the older cost-of-performance method some states still use. Get the sourcing method wrong, and you can end up overpaying one state, underpaying another, or triggering a notice you did not see coming.
What Is Apportionment, and Why Does It Matter?
Apportionment is the formula a state uses to decide what slice of your company’s total income it gets to tax. No state taxes 100% of a multi-state company’s income. And no company gets to pick which state taxes which dollar. Instead, each state where you have nexus, meaning a strong enough connection to be subject to its tax, applies its own formula to your total income.
Most states, Georgia included, now use a single sales factor formula. Your apportionment percentage depends entirely on where your sales occurred, not on where your offices, equipment, or payroll sit. Property and payroll used to matter under the old three-factor formula. That’s mostly gone now. What’s left is the harder question: how do you decide where a sale “occurred” when the customer sits in one state and the work happened in another?
That’s where the two sourcing methods split.
Cost of Performance vs. Market-Based Sourcing: What’s the Difference?
- Cost of performance sources a sale to wherever the greater share of the work was actually done, usually wherever your employees or contractors sat while performing the service.
- Market-based sourcing sources the same sale to wherever your customer received the benefit, regardless of where your team worked from.
The distinction sounds academic until you run the numbers. A Georgia-based consulting firm with clients in ten states looks completely different under each method. Under cost of performance, nearly all of that income stays in Georgia, because that’s where the consultants sit. Under market-based sourcing, the income follows the clients instead. Georgia only taxes the portion tied to its own customers.
| Aspect | Cost of Performance | Market-Based Sourcing |
|---|---|---|
| How income is sourced | Where the service is performed | Where the customer receives the benefit |
| Where it’s still used | A shrinking number of states | Most states, including Georgia |
| Who it tends to favor | Businesses based in high-tax states with mostly out-of-state customers | Businesses whose customers sit in low-tax states |
| Main risk | Double taxation if another state claims the sale under a different method | The same risk, in reverse, when sourcing rules don’t line up across states |
A Worked Example
Say a Georgia-based marketing agency bills $2,000,000 in fees for the year. Of that, $600,000 comes from Georgia clients. The other $1,400,000 comes from clients in other states, and the agency’s staff does all the work from its Atlanta office.
Under cost of performance, Georgia could tax close to the full $2,000,000, since that’s where the work happened. Georgia doesn’t use that method, though. Under market-based sourcing, only the $600,000 tied to Georgia-based customers counts toward Georgia’s apportionment factor. The other $1,400,000 follows the client’s location instead, and depending on where those clients sit, it may or may not get taxed anywhere at all. That gap is exactly why the sourcing method matters more than most business owners assume. It decides which state’s rate applies to nearly three-quarters of this agency’s revenue.
How Georgia Treats Apportionment (As of 2026)
Georgia uses a single sales factor formula for corporate income tax, set out in Official Code of Georgia Annotated (O.C.G.A.) § 48-7-31. Property and payroll no longer factor into your apportionment percentage at all. For service businesses, the same statute sources receipts using market-based, or “marketplace,” sourcing. Income counts as Georgia’s when the customer receives the benefit here, not simply because your team performed the work from a Georgia office.
Georgia also has no throwback rule. Nothing in § 48-7-31 pulls an out-of-state sale back into Georgia’s tax base just because you have no nexus where the customer sits. In states that use a throwback rule, that same sale gets “thrown back,” and your home state taxes it instead, on the theory that the sale has to land somewhere. Georgia skips this step. That can work in your favor if you sell into states where you have no filing obligation. It also means the reverse can happen, income taxed nowhere at all, which is worth flagging to your CPA rather than assuming it will sort itself out.
None of this is static. Georgia’s rules can shift with each legislative session, and this summary reflects the rules in effect for 2026. If you’re weighing a move or an expansion, our Atlanta accounting team can walk through how it would actually apportion under current law before you commit.
What This Looks Like in Practice
One pattern we see often with Atlanta-based service firms: a marketing or consulting business grows past its home market. It picks up clients in three or four other states along the way. It keeps filing taxes the same way it always has, because nothing about day-to-day operations changed. The tax exposure changed anyway. Once a meaningful share of revenue ties to out-of-state customers, market-based sourcing shifts a real chunk of income out of Georgia’s tax base. That income lands in the states where those customers sit instead, which can mean new filing obligations the business never had before. (This reflects a common situation across clients, not any single company’s facts.)
Do You Have Nexus in Other States?
Nexus is the connection that gives a state the right to tax you at all, before apportionment even enters the picture. It can be physical, an office, employees, or inventory sitting in a warehouse. Or it can be economic: you’ve crossed a sales or transaction threshold a state has set, even without setting foot there.
Selling online adds a layer many business owners don’t expect. If your products sit in a fulfillment center in another state, that inventory alone can create nexus there. Several states also apply an economic nexus standard modeled on the Multistate Tax Commission’s guidance, roughly $500,000 in sales attributed to the state. The exact figure varies by state and changes over time, so treat that as a benchmark, not a rule to rely on directly.
This is a separate question from sales tax nexus, which runs on its own thresholds. If sales tax compliance is the concern, that’s a distinct conversation, worth raising with a sales tax specialist directly rather than folding into an income tax review.
Plan Ahead Before You Expand Across State Lines
Before entering a new state, most businesses work through the same handful of questions with their CPA:
- What the new state’s nexus threshold actually is.
- Whether that state uses cost of performance or market-based sourcing.
- Whether a throwback rule could pull income back into the home state.
- How the numbers change once apportionment is applied.
Skipping this step doesn’t make the obligation disappear. It just means you find out later, usually from a notice instead of a plan.
Ready to map this out for your business? Schedule a discovery call and we’ll walk through how apportionment applies to where you actually do business.
Frequently Asked Questions About Georgia Apportionment
What’s the difference between cost of performance and market-based apportionment?
Cost of performance sources income to wherever the work was done. Market-based sourcing, which Georgia uses for most service businesses, sources the same income to wherever the customer received the benefit. The two methods can produce very different tax bills for the same business.
How do I know which states I owe corporate income tax to?
You owe tax in any state where you have nexus, physical (an office, inventory) or economic (crossing a sales threshold). Each state then applies its own apportionment formula to figure out how much of your income it can tax.
Does Georgia have a throwback rule?
No. O.C.G.A. § 48-7-31 doesn’t include one, so Georgia does not throw back sales made to states where you have no nexus. That’s generally favorable if you sell into states where you don’t currently file. It’s still worth checking whether the states you do have nexus in use a throwback rule of their own.
Why does apportionment matter for e-commerce and online sellers?
Because market-based sourcing means your customer’s location, not your warehouse or office, often decides where income gets taxed. For a business selling nationwide, that can shift a meaningful share of income outside the state where the company is actually based.
About this article and how we use AI
This article is provided for general informational and educational purposes only and does not constitute tax, legal, accounting, or financial advice. Tax laws change and apply differently depending on your specific circumstances. Nothing here creates a client relationship with Fusion CPA, and it should not be relied upon or acted on without consulting a qualified professional about your own situation. To discuss how these rules apply to you, contact Fusion CPA at info@fusiontaxes.com.
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