Multiple Tax IDs in SimplePractice: Set Claim Rules
By George Ruan • October 7, 2026
Last reviewed: October 7, 2026.
To bill under more than one tax ID in SimplePractice, keep the most common entity as the default billing provider and add claim rules for the exceptions, for example a clinician or payer whose claims go out under a different tax ID. A rule changes what is printed on the claim. It does not enroll that tax ID with the payer.
SimplePractice’s claim rules article says rules replaced billing profiles and are available on all plans, so older advice that you need the Plus plan for billing profiles is out of date.
Sections
Write down which entity bills what
Before touching settings, list each combination of clinician, payer, location, and date range with the tax ID, billing NPI, and payer enrollment that applies. Settings should follow that list, not the other way round.
Tax ID problems we actually run into
The EHR and the W-9 disagree. During onboarding we have found SimplePractice listing a different tax ID from the W-9 the practice had just signed. The answer was a planned move to a new EIN, with demographic updates already sent to payers. Ask before assuming either one is a typo.
A wrong digit on a claim. A practice caught a mistyped EIN on a claim. Fixing the tax ID in SimplePractice corrected future claims, but not the one already sent; that claim had to be corrected and resubmitted.
Two billers on one account. When one biller handles one entity and someone else handles another inside the same account, it becomes unclear who owes what. We ask practices to give one biller all the insurance billing in an account, or put the other entity in a separate EHR account.
Set up a narrow rule
Go to Settings > Client billing and Insurance > Insurance billing and check Default billing provider info.
Under Claim rule automation, choose Create rule or Add rule, and name it after the entity and scenario.
Set IF conditions for clinician, payer, location, or CPT code. Leaving a condition out means it applies to everything.
Under THEN, add the fields to override (tax ID, billing NPI, name, address), then Save rule.
To change a rule, duplicate it, edit the copy, save, and turn off the original. Rules cannot be edited in place.
Check before you send
Open a claim the rule should affect and one it should not. Compare the tax ID, billing NPI, rendering NPI, name, and address with your list. If two rules can change the same field, fix the overlap first.
Then confirm the payer actually has that tax ID enrolled, with claims, remittances (ERA), and direct deposit (EFT) set up for it. Keep claims for earlier dates under the tax ID that applied then. If you are replacing an EIN rather than running two, use the EIN change checklist. For taxonomy rejections, see rendering versus billing taxonomy.
Frequently Asked Questions
I fixed the tax ID in SimplePractice. Are old claims fixed too?
No. The change applies to new claims. Claims already sent with the wrong tax ID need a corrected claim.
Do I need the Plus plan for multiple tax IDs?
Not anymore. SimplePractice says claim rules, which replaced billing profiles, are available on all plans.
Can I switch tax IDs to get a rejected claim through?
Only if the original tax ID was wrong. Using another entity’s tax ID to get around an enrollment problem creates a bigger one.
Sources
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Founded by George Ruan, Dax Earl, and Andrey Goder, Bomi helps independent therapists and group practices with insurance billing, credentialing, and payer follow-up. Bomi grew out of Dax’s experience helping his mother with her therapy practice, with a clear purpose: reduce the administrative burden of insurance while keeping practice owners in control.
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