Switching Billers: Who Handles Old Claims?
By George Ruan • October 7, 2026
Last reviewed: October 7, 2026.
When you switch billers, split the work by date of service. The new biller files claims for visits on or after the start date; the outgoing biller keeps working the claims it already submitted until its last day. Anything left after that, such as denials and unpaid claims, needs a named owner in writing, or it will sit untouched.
Sections
Pick one cutoff date and tell both billers
A clean handoff starts with one date. Claims for visits before it belong to the outgoing biller, including payments that arrive after the new biller starts. Claims for visits on or after it belong to the new biller. Tell the outgoing biller to submit claims only for visits before the cutoff, so the same visit is not filed twice.
Outgoing billers often have a notice period, so their last day may come weeks after the new biller starts. During that overlap, each biller works only its own side of the cutoff. When the outgoing biller leaves, decide whether its unfinished claims come back to the practice or go to the new biller. At Bomi, we can take over cleanup of a prior biller’s claims once they have left, as long as those claims live in the practice’s EHR. We do not work the same account alongside another active biller.
Where handoffs usually break
In the transitions we have taken over, the same gaps come up again and again:
Visits that fall between the two billers. An outgoing service may stop filing new claims on a set date. A visit from before that date whose note is signed after it never gets filed. Ask the outgoing biller which unsigned or unfiled visits it will not touch, and assign them.
Claims that look stuck but have a known cause. On one open-claims list we received, the reasons included a wrong payer ID, coordination of benefits the client never updated, a prior authorization the payer required, and an out-of-network plan. Each needs a different fix. Ask for the reason, not just the age of each claim.
Denials moved to the client. Some billers move denied claims to client responsibility or a “not covered” status before they leave. Keep those claims on file. If the client later fixes the coverage problem, the claim may still be workable.
Two billers on one account. When the practice, an old biller, and a new biller all touch the same claims, you get duplicate filings and records nobody can reconcile. Keep one responsible party per claim from start to finish.
What to ask the outgoing biller for
A list of every open claim with its date of service, payer, current status, and the next step they planned.
The last date it filed new claims, and any visits it held back (unsigned notes, missing insurance details, coding questions).
Unanswered payer requests, such as records requests, authorization requests, or coordination-of-benefits questions.
Patient credits, refunds in progress, payment plans, and balances it has already sent to clients.
The date its EHR and portal access ends. Remove its access on that date and make sure the new biller has its own login.
If the outgoing biller used a messaging tool inside the EHR, such as claim support messages, review those threads before access ends. They often hold the only record of what the payer asked for.
Do not resubmit everything that looks unpaid
An unpaid claim may be pending, denied, or paid but not posted. Check its status with the payer before you send anything new. A claim that already has a payer claim number was received, even if a later status check says “not found”. Sending it again just creates a duplicate denial. Fix the cause, then send a corrected claim or follow the payer’s appeal process.
SimplePractice also notes that transferring account data does not change how payers process claims already sent. For payments received outside the EHR, SimplePractice documents manual payment recording. Decide who posts late payments on old claims, so the same deposit is not posted twice.
For the ongoing split of responsibilities, see how to work with your biller. If you are changing EHRs at the same time, use the EHR switch checklist for unpaid claims.
Frequently Asked Questions
Does my new biller automatically take over old claims?
No. Unless you agree otherwise, a new biller starts with visits on or after its start date. Old claims stay with the previous biller until its last day; after that, assign them to someone in writing.
Who gets payments that arrive after the switch?
Whoever owns that date of service. A payment for an earlier visit belongs to the outgoing biller’s work, even if it arrives after the new biller has started.
Can the old biller and new biller share the account for a while?
They can share the overlap period if each works only its own side of the cutoff date. Having both work the same claims leads to duplicate submissions, which is why Bomi will not co-work claims with another active biller.
Sources
SimplePractice: Recording payments from external billing platforms
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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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