By Daniel Sabet · CFO & Financial Advisor, GreenGrowth CPAs · Tax Strategy & Growth Planning · Los Angeles, CA | Published August 2026 | Tax Advisory
Most coverage of the California SaaS sales tax speaks to buyers, and the message is that subscriptions get more expensive. True, and the smaller half of the story. The harder half falls on sellers. Uncollected tax stays the seller’s liability, not the buyer’s. A software company that never registered in California, because its sales were not taxable, may cross the nexus threshold on day one of 2027. Nothing will be in place.
QUICK ANSWER
The California SaaS sales tax starts January 1, 2027 under SB 122, signed June 29, 2026. Prewritten software becomes taxable regardless of delivery method. Downloads, licences and remotely accessed cloud applications all fall in scope. Custom software stays exempt. Sellers with California nexus must register with the CDTFA and collect. Economic nexus sits at $500,000 in gross California sales, and your newly taxable software revenue counts toward that figure. Uncollected tax remains the seller’s liability.
California SaaS Sales Tax: At a Glance
What Software Sellers Need to Know Before January
- Delivery method stops mattering: SB 122 makes prewritten software taxable tangible personal property, whether you download, licence or stream it.
- No California office does not help: Economic nexus turns on your sales, not your address. The threshold is $500,000 in gross California sales, current or prior calendar year.
- Your own sales push you over: Newly taxable software revenue counts toward that threshold. A company at $450,000 today crosses it immediately.
- The liability is yours: Uncollected tax stays with the seller. CDTFA can look back three years, and eight years for a seller who never registered.
- Custom software remains exempt: Modifications to prewritten software qualify only to the extent of the modification, and only when invoiced separately.
- One rule no other state has: Where sales to a single purchaser exceed $5 million, that purchaser self-assesses and remits the use tax instead.
- GreenGrowth’s role: We run nexus studies, handle CDTFA registration and classify product catalogues. Book a nexus review →
What SB 122 Changed About Software Taxability
Before the California SaaS sales tax, the state was one of the last major economies leaving SaaS outside its sales tax base. Taxability turned on delivery. Software on a disc counted as tangible personal property and taxed accordingly. The same software delivered electronically did not.
SB 122 removes that distinction. From January 1, 2027, prewritten software counts as tangible personal property however it reaches the customer. The full 7.25% state rate applies, plus local district taxes varying by the buyer’s location.
SB 122 covers more than software. For the business credit cap and the reduced first-year LLC tax, see our guide to the 2026 California tax changes under SB 122. This piece stays on the seller side.
Where the Prewritten and Custom Line Falls
Custom software remains exempt. Modifications to prewritten software count as custom only to the extent of the modification. The exemption then applies only when those charges appear separately on the invoice.
That sounds clean and rarely is. Configurable platforms, bundled implementation services, and professional services sold alongside a licence all sit near the line. So classify the catalogue product by product before January. The answer decides whether you collect at all.
💬 The Conversation Worth Having
The companies most exposed here are the ones who did nothing wrong. A software business selling into California has had no reason to register, because its product was not taxable. It never tracked California revenue as a compliance number. Now that revenue counts toward a threshold it never watched, and the first time anyone runs the figure is often after the obligation has already started. That is not a tax planning problem. It is a bookkeeping question nobody thought to ask.
Do you know your California revenue for the last twelve months, across every channel?
Who Owes the California SaaS Sales Tax
The California SaaS sales tax does not create a new nexus test. It makes software sales count toward the existing one, which is why so many companies will register in California for the first time.
Physical nexus. Employees, contractors, an office, leased property or inventory in the state, including stock in a third-party warehouse. Physical nexus registers you from the first dollar.
Economic nexus. More than $500,000 in gross California sales during the current or prior calendar year, across all channels including marketplace sales. California dropped its transaction count threshold in 2019, so dollar volume is the only test.
The trap. Your newly taxable software revenue counts toward that $500,000. So a company running $450,000 in California SaaS sales, never registered because those sales were not taxable, crosses on day one of 2027. Nexus triggers the day you exceed the amount, not at quarter end.
Why the California SaaS Sales Tax Is a Seller Problem
If you should have collected and did not, the state comes to you rather than your customer. You can try billing customers retroactively for tax you never charged. In practice most of that goes uncollected, particularly on churned accounts.
The lookback makes it worse. CDTFA can generally assess back three years from the return due date. For a seller who never registered and never filed, that window stretches to eight years. So missing the California SaaS sales tax does not cost one year of tax. It compounds quietly until someone notices.
The $5 Million Rule Nobody Else Has
The California SaaS sales tax includes a mechanism no other state currently uses, and enterprise sellers should model it now.
Where a retailer’s gross receipts from digital product sales to a single purchaser exceed $5 million in the applicable period, the obligation shifts. The purchaser then self-assesses and remits use tax directly, rather than the seller collecting it.
Two groups need to plan around it. Sellers with very large accounts must know which relationships cross the line, since collecting tax you should not have collected creates its own problem. Buyers with heavy software spend may owe use tax directly, whether or not a vendor invoice shows any.
Either way it needs contractual coordination. Enterprise agreements written before this rule existed rarely say anything useful about who remits.
California SaaS Sales Tax: What to Do Before January
Preparing for the California SaaS sales tax takes longer than it looks. Registrations, system changes and customer conversations all consume real time.
▶ Five Steps, In Order
| Step | What It Involves | Why It Comes First |
|---|---|---|
| 1. Nexus study | Pull California sales across every channel for the last twelve months, plus physical presence | Everything else depends on the answer |
| 2. Classify the catalogue | Prewritten, custom or bundled, product by product | Determines what you collect on |
| 3. Register with CDTFA | Applications may be filed up to 90 days before the effective date | Registering late is far worse than early |
| 4. Fix billing and sourcing | Capture purchaser address fields, apply state and district rates by buyer location | Rates vary by city, not just by state |
| 5. Collect exemption certificates | Resale buyers and qualifying exempt entities | Missing certificates make exempt sales taxable |
Test renewals, upgrades, mid-cycle changes and credits before January. Straddling contracts that span the effective date need their own answer.
If You Discover Exposure in Another State
A California nexus review often surfaces something else. Companies pulling multistate revenue for the first time frequently find they should have registered elsewhere already.
Address that before registering rather than after. A voluntary disclosure agreement is generally available only while a state has not yet contacted you, so registering can close that door. Confirm current CDTFA guidance directly at the California Department of Tax and Fee Administration, since implementation detail is still emerging.
How GreenGrowth CPAs Handles California SaaS Sales Tax
Our California SaaS sales tax work runs in three parts. First, a nexus study establishing whether you have an obligation at all, in California and anywhere else the review surfaces. Second, product classification against the prewritten and custom line, where bundled platforms get argued. Third, registration and the operational build, covering sourcing fields, rate configuration and exemption certificates.
Companies that handle this well start with the nexus number rather than with software. A tax engine calculates rates accurately. It cannot tell you whether you have nexus, whether your product is prewritten, or which contracts straddle the effective date. Those stay judgment calls.
You can see the wider practice on our tax planning and compliance page.
KEY TAKEAWAYS
- ›From January 1, 2027, prewritten software is taxable in California regardless of delivery method. The rate is 7.25% plus local district taxes sourced to the buyer’s location.
- ›SB 122 does not create a new nexus test. It makes software sales count toward the existing $500,000 threshold, so many sellers register in California for the first time.
- ›A company at $450,000 in California software revenue today crosses the threshold on day one of 2027. Nexus triggers when you exceed the amount, not at quarter end.
- ›Uncollected tax stays the seller’s liability. CDTFA can assess back three years, or eight for a seller who never registered.
- ›Where sales to a single purchaser exceed $5 million, that purchaser self-assesses and remits use tax instead. No other state uses this mechanism, and enterprise contracts rarely address it.
- ›Start with the nexus number, not with software. A tax engine calculates rates. It cannot tell you whether you have nexus or whether your product is prewritten.
California SaaS Tax Questions Answered
Scope and Timing
When does the California SaaS sales tax start?+
January 1, 2027. Governor Newsom signed SB 122 on June 29, 2026 as part of the 2026-27 budget package. No phase-in period applies. Prewritten software becomes taxable on that date at the 7.25% state rate, plus local district taxes sourced to the buyer’s California location.
Is custom software still exempt in California?+
Yes. Custom software remains outside the tax. Modifications to prewritten software qualify as custom only to the extent of the modification. The exemption applies only where those charges appear separately on the invoice. Configurable platforms and bundled implementation services sit close to the line, so both need product-level classification.
Does it matter how I deliver the software?+
No, and that is the core of the change. California previously taxed software on physical media while exempting the same product delivered electronically. SB 122 reclassifies prewritten software as tangible personal property regardless of delivery. Downloads, term or perpetual licences and remotely accessed cloud applications all fall in scope.
Nexus and Liability
Do I need to register if I have no California office?+
Possibly. Economic nexus turns on sales rather than location. You have an obligation if your gross California sales exceed $500,000 in the current or prior calendar year. That counts all channels, including marketplace sales. California removed its transaction count threshold in 2019, so dollar volume is the only test.
Do my software sales count toward the $500,000 threshold?+
Yes, once SB 122 takes effect. That is the trap most companies miss. Take a software business running $450,000 in California sales. It never registered, because those sales were not taxable. It crosses the threshold on day one of 2027 with no grace period. Nexus triggers the day you exceed the amount, not at quarter or year end.
What happens if I do not collect the tax?+
Uncollected tax remains the seller’s liability, not the buyer’s. You can attempt to bill customers retroactively. In practice much of that goes uncollected, especially on churned accounts. CDTFA can generally assess back three years from the return due date. That window stretches to eight years for a seller who never registered or filed.
Enterprise Deals and Next Steps
What is the $5 million self-remittance rule?+
Where a retailer’s gross receipts from digital product sales to a single purchaser exceed $5 million in the applicable period, the purchaser self-assesses and remits use tax directly. The seller does not collect it. No other state currently uses this mechanism. Enterprise agreements written before the rule existed rarely address who remits, so large relationships need contractual coordination.
When should I register with the CDTFA?+
Applications may generally be submitted up to 90 days before the effective date. So handle registration in advance rather than in January. Run the nexus study first. If that review surfaces exposure in another state, address it before registering anywhere. A voluntary disclosure agreement is typically available only while a state has not yet made contact.
Working With GreenGrowth CPAs
How does GreenGrowth CPAs help with SB 122 compliance?+
We run the nexus study across California and any other state the review surfaces. We classify the product catalogue against the prewritten and custom line, then handle CDTFA registration. We also work through the operational build, covering sourcing fields, rate configuration and exemption certificates. GreenGrowth CPAs works with technology and software companies alongside our other industry practices.
Uncollected Tax Is Your Liability, Not Your Customer’s.
Book a California nexus review. We establish whether you cross the threshold, classify your catalogue and handle registration before the January deadline.
GreenGrowth CPAs · Tax Advisory Team
