Medical Billing Company Transition: Who Manages Old A/R, Appeals and Pending Claims?

Your medical practice has decided to change billing companies.

The current company has been missing follow-ups, insurance payments are taking longer than expected, and your staff spends too much time asking for updates on unpaid claims.

You find a new billing partner, agree on a starting date, and prepare to make the change.

But there is one important question:

What happens to all the claims your previous billing company hasn’t finished?

Some claims have already been submitted to insurance companies. Others were denied and need further attention. A few may be waiting for medical records, while payments from earlier claims may still be arriving.

For practices switching medical billing companies, these unfinished tasks can become a bigger problem than the actual change of vendor.

A billing transition should not interrupt the practice’s ability to collect payment for services already provided.

The key is deciding who handles every outstanding claim before the previous company stops working.

Why Does Switching Medical Billing Companies Put Revenue at Risk?

Changing billing companies is different from replacing an ordinary office service.

Your billing company is responsible for submitting insurance claims, tracking payments, following up on denials, and keeping financial records updated.

Those activities do not stop when you sign a contract with a new vendor.

Imagine a family medicine practice moving to a new billing company on November 1.

The incoming company begins submitting claims for November appointments. However, the previous company still has unpaid claims from August, September, and October.

Some have been denied. Others are awaiting payer responses.

If neither company has agreed to manage those older accounts, the claims may remain untouched for weeks.

Meanwhile, the practice continues paying salaries, rent, and other expenses without receiving the expected reimbursement.

This is why a medical billing transition needs more than a software setup and a starting date.

Every unfinished claim needs a clear owner, a next action, and a deadline.

Before making a change, practices should also evaluate whether their new partner can support their specific billing needs. Our guide to choosing a medical billing company explains the questions healthcare providers should ask before hiring a new vendor.

What Happens to Old A/R When You Change Billing Companies?

Accounts receivable, commonly called A/R, refers to money that is still owed to the practice for services already billed.

This may include unpaid insurance balances, outstanding patient balances, and claims awaiting final payment.

When a practice changes billing companies, old A/R does not automatically move to the new vendor’s responsibility.

Who manages it depends on the agreements made with the outgoing and incoming companies.

There are three common approaches.

Option 1: The Previous Billing Company Continues Managing Old A/R

Under this arrangement, the outgoing billing company remains responsible for the claims it handled before the transition.

For example, the previous company may continue following up on October claims while the new company manages services provided from November onward.

This can make the transition easier because the original billing team already knows the history of those claims.

However, the practice needs to consider several questions.

Will the old company continue working denials? How long will follow-up services continue? Will additional fees apply? How will the practice receive updates?

There is also a practical challenge when two companies need access to the same billing system.

The important step is to document exactly what the previous company will continue handling and when that responsibility ends.

Option 2: The New Billing Company Takes Over Existing A/R

Some practices prefer to transfer outstanding claims to the incoming billing company.

This can provide one team with responsibility for both new claims and historical balances.

However, taking over old A/R requires more than receiving a spreadsheet of unpaid amounts.

The incoming team needs claim histories, previous payer responses, denial reasons, appeal records, payment information, and access to relevant supporting documents.

Without those details, staff may spend considerable time investigating problems that the previous company already reviewed.

The new contract should also explain whether old A/R recovery is included in the regular billing fee or charged separately.

A new billing company should not be assumed to manage historical claims unless that work is included in its agreed scope.

Option 3: Both Companies Divide the Responsibility

A third option is to divide the work.

For example, the outgoing company might finish appeals already submitted, while the incoming company handles new claims and selected unpaid accounts.

This arrangement can work, but only when responsibilities are clearly defined.

Otherwise, both companies may assume the other is handling a particular claim.

The practice should specify which company manages each group of claims and who is responsible for reporting progress.

There should also be one clear point of contact for resolving disputes about claim ownership.

What Counts as an Unfinished Claim During a Billing Transition?

One common mistake is assuming old A/R includes every billing task that existed before the transition.

In reality, practices may have several types of unfinished work:

• Unbilled encounters: Patients received services, but the claims have not yet been prepared or submitted.
• Pending claims: Claims were submitted, but the insurance company has not issued a final payment decision.
• Rejected claims: Claims failed an initial processing check and need correction before they can move forward.
• Denied claims and active appeals: Claims require investigation, reconsideration, or supporting documentation.
• Paid but unposted claims: Insurance payments have been received, but the corresponding billing records have not been updated.

These categories require different actions.

For example, a claim waiting for payment should not be resubmitted simply because a new billing company has taken over.

Doing so could create duplicate-claim problems.

Likewise, a denied claim may have an appeal deadline that cannot be extended just because the practice changed vendors.

The new billing team needs to understand what has already happened before deciding what happens next.

Review Your Current Billing Contract Before Making the Switch

Before ending a billing relationship, practice owners should review the existing service agreement.

A contract may specify how much notice is required, whether fees remain payable, what happens to outstanding claims, and what support the outgoing company must provide.

Pay particular attention to the treatment of historical collections.

For example, the outgoing vendor may be entitled to an agreed fee for certain payments received after the contract ends. Whether such fees apply depends on the contract.

The practice should also review its rights to billing records, claim histories, reports, and system access.

Patient information needs special attention.

Under the HHS HIPAA business associate guidance, business associate agreements generally address the return or destruction of protected health information when a relationship ends, subject to applicable requirements and exceptions.

HHS also explains that a business associate generally cannot block a covered healthcare provider’s access to protected health information it maintains on that provider’s behalf.

This makes it important to arrange a secure, usable data transfer before the outgoing company’s operational access is discontinued.

Practices considering a new partner can also review our medical billing outsourcing guide for broader information about vendor responsibilities and onboarding.

Build a Complete Claim Inventory Before the Cutover Date

The cutover date is the point when the new billing company officially begins taking responsibility for the work assigned to it.

Before that date arrives, the practice should request a complete inventory of unfinished billing activities.

For each outstanding claim, the report should ideally identify the patient account, claim number, date of service, insurance payer, remaining balance, current status, and most recent action.

Claims requiring correction or appeal should also include their applicable deadlines.

Most importantly, each account needs an assigned owner.

For example, if an insurance company requests medical records on October 28 and the practice changes billing vendors on November 1, someone must be responsible for submitting those records and following up on the decision.

Without a documented handoff, the request may simply be overlooked.

Original Medicare generally requires claims to be submitted within one calendar year of the date of service, subject to limited exceptions. The CMS timely filing guidance explains this requirement.

Changing billing companies does not restart that deadline.

An initial medical billing audit can help the practice understand the value of outstanding balances and identify unresolved issues before transferring responsibility.

Before the switch, the outgoing and incoming teams should reconcile the old A/R report so the practice knows which claims have been transferred, which remain with the previous company, and which need immediate attention.

The most important rule is simple: no claim should be left without someone responsible for its next step.

Once the old A/R inventory is ready, the practice can move on to the next challenge: transferring active appeals, pending claims, clearinghouse information, and payment records without interrupting daily billing operations.

Who Handles Pending Insurance Claims During a Billing Transition?

One of the biggest concerns when switching medical billing companies is what happens to claims that have already been submitted but haven’t been paid.

These claims don’t automatically become the responsibility of the new billing company.

The practice must decide who will continue working them, confirm that arrangement with both vendors, and keep a record of every account that needs attention.

A good transition plan separates unfinished claims into three groups.

Claims Submitted Before the Transition Date

Imagine a practice switches billing companies on November 1. The outgoing company submitted 200 claims during October, but the insurance companies haven’t processed all of them yet.

Those claims are still active, even though the previous vendor’s regular work has ended.

If the outgoing company has agreed to finish them, it should continue monitoring payer responses and reporting progress.

If the incoming company takes responsibility, it needs the original claim numbers, submission dates, payer acknowledgments, and follow-up history.

The practice should never assume that a submitted claim will be paid without further attention.

Some claims may require additional medical records, corrections, or responses to payer requests before payment can be released.

Rejected Claims That Need Correction

A rejected claim is generally one that hasn’t passed an initial processing check.

For example, the clearinghouse may reject a claim because the patient’s insurance identification is incorrect or required provider information is missing.

These claims usually need to be corrected and submitted properly.

During a billing transition, the danger is that the outgoing company assumes the new team will fix them, while the incoming company doesn’t know they exist.

The result could be a claim that remains unsubmitted until the filing deadline passes.

Practical fix: Export a separate list of rejected claims, including the rejection reason, original submission attempt, required correction, and assigned billing team.

Claims Denied Before the New Company Takes Over

Denied claims require a different approach.

An insurance company may have accepted and processed a claim but refused payment because of a coding problem, missing authorization, or coverage issue.

The outgoing billing team may already have contacted the payer or collected documents for an appeal.

If that history isn’t transferred, the new team may repeat the investigation or miss an important deadline.

This is why historical denial records should be treated as an essential part of the billing handoff.

Our Denial Management Services explain how claim investigations, corrections, appeals, and payer follow-up support revenue recovery.

What Happens to Appeals Already in Progress?

An appeal is a formal request asking an insurance company to reconsider a payment decision.

Some appeals can take weeks or months to resolve. A practice may therefore have several active appeals when it decides to change billing companies.

For example, the outgoing vendor may have appealed a denied surgical claim but received no response before the transition.

The incoming team needs to know when the appeal was submitted, which documents were provided, the payer’s tracking number, and whether another response is required.

If the appeal has not yet been submitted, the new team must know the filing deadline.

For Original Medicare, a first-level redetermination generally must be requested within 120 days of receiving the initial claim determination. Commercial insurance and Medicare Advantage appeal rules may differ.

The CMS Medicare Redetermination guidance explains the Original Medicare process.

Changing billing companies does not restart an appeal deadline.

Before the transition, practices should therefore confirm which vendor will prepare, submit, and monitor every unfinished appeal.

A Practical Medical Billing Company Transition Responsibility Matrix

A written responsibility matrix can prevent confusion between the outgoing vendor, incoming vendor, and practice management.

The following example shows one possible arrangement when the new billing company has agreed to take over unfinished claims.

This is an example, not a rule that every practice must follow.

Some practices prefer the previous vendor to finish historical claims. Others transfer nearly everything to the new company.

The essential requirement is that each task has one clearly accountable owner, with practice management overseeing the handoff.

Transfer EHR, Clearinghouse and Payer Access Safely

Billing teams need access to several systems to prepare claims, review payment decisions, and follow up with insurers.

These commonly include the electronic health record (EHR), practice management software, clearinghouse, and insurance payer portals.

A clearinghouse is a service that checks and forwards electronic claims to insurance companies. It also returns important processing messages.

When vendors change, the practice should verify that the incoming billing team can access the necessary information before disabling the outgoing team’s access.

This does not mean sharing passwords between companies.

Each authorized user should have appropriate individual access, and the practice should review permissions after the handoff.

Some payer and clearinghouse arrangements may also require the practice to update its electronic claim submitter information or remittance delivery settings.

Patient information must be transferred securely.

The HHS guidance on access to protected health information explains that business associates generally cannot block a healthcare provider’s access to the protected health information they maintain on the provider’s behalf.

The practice should also review its business associate agreements and ensure the incoming vendor has the required privacy and security arrangements in place.

How to Prevent Lost Payments and Duplicate Claims

Changing billing companies can create confusion when money continues arriving for claims submitted by the previous vendor.

Two important terms help explain the problem.

Electronic Funds Transfer (EFT) is the system used to deposit insurance payments into the provider’s bank account.

Electronic Remittance Advice (ERA) is the electronic statement explaining which claims were paid, denied, or adjusted.

These are related, but they are not the same.

A practice might continue receiving deposits while the new billing team has no access to the corresponding remittance records.

That can leave payments unposted and patient account balances incorrect.

The CMS Payment and Remittance Advice guidance explains how remittance information supports payment posting and reconciliation.

Before switching vendors, confirm that payer payments continue reaching the correct practice-controlled bank account and that the appropriate team receives the ERA files or other remittance information.

Both vendors should also coordinate payment posting so the same payment is not recorded twice.

The incoming team must review a claim’s history before submitting it again. An unpaid balance does not necessarily mean the insurer never received the original claim.

What Should Happen on the Official Transition Date?

The transition date should mark a controlled handoff, not the moment everyone begins figuring out which systems and claims need attention.

Before the new billing company starts regular processing, the practice should confirm that:

1. The old A/R inventory has been reconciled and assigned.
2. The incoming billing team can access the required systems and payer information.
3. Claim submission and clearinghouse connections have been tested.
4. Active appeals and filing deadlines are assigned to responsible staff.
5. ERA delivery, EFT arrangements, and payment posting responsibilities are confirmed.
6. Both vendors understand how unresolved claims will be reported and escalated.

The practice should retain a final copy of the transition inventory and document any outstanding disagreements.

A successful billing-company handoff is not measured only by whether the new team can submit its first claim. It is measured by whether existing revenue continues to move through the billing process without losing accountability.

Once the transition is complete, practice management should closely monitor both new claim activity and historical balances.

The first 30 days are especially important for identifying missing claims, delayed payments, and unfinished tasks that were overlooked during the handoff.

What Should a Practice Monitor During the First 30 Days After Switching Billing Companies?

The first month after changing billing companies is when practices discover whether the handoff was actually completed properly.

The new team may be submitting claims successfully, but older accounts could still be waiting for follow-up. Insurance payments might be reaching the bank while remittance records remain unavailable. Some patient encounters may not have been transferred at all.

These problems are easier to correct when they are identified early.

The First Week: Confirm That Billing Is Working

During the first several days, practice management should make sure that new patient encounters are reaching the billing system and that claims are being submitted and accepted for processing.

The team should also confirm that payment information is arriving, rejected claims are being corrected, and no accounts are sitting without an assigned owner.

For example, if a practice changes vendors on November 1 but discovers on November 7 that claims from one location haven’t been submitted, the problem can be investigated before it affects an entire month of revenue.

Practical fix: Review claim submission reports, rejection reports, payment postings, and unresolved transition tasks daily during the initial handoff.

Weeks Two Through Four: Check the Money, Not Just the Claims

Once claim submission is working, the practice should compare financial results with its pre-transition baseline.

Are insurance payments being posted correctly? Are denied claims receiving follow-up? Is old A/R decreasing because claims are being resolved?

Some payment delays are normal when changing processes, but unexplained gaps should not be ignored.

A useful approach is to compare the new billing company’s reports with the final balances and claim inventory transferred from the previous vendor.

The goal is to confirm that the new billing process works while historical revenue continues to receive attention.

How to Recover Old A/R After Switching Medical Billing Companies

Old accounts receivable does not automatically become bad debt simply because a practice changes vendors.

Some unpaid claims may still qualify for payment after an appropriate correction, documentation submission, payer follow-up, or appeal.

However, the recovery process should begin with an honest assessment of what is still collectible.

Separate Recoverable Claims From Unresolved Administrative Problems

A new billing team should review historical balances and identify why each account remains open.

For example, one claim may be unpaid because the insurer never received the required medical record. Another may already have been denied because of a coding error.

A third claim may have been paid, but the payment was never posted correctly.

These situations require different actions.

Rather than repeatedly resubmitting every old claim, billing teams should confirm what happened and determine the appropriate next step.

Claims should also be reviewed for timely filing limits, appeal deadlines, payer contracts, and supporting documentation.

A claim that is no longer eligible for payment should not be presented as guaranteed recoverable revenue.

Prioritize Claims That Need Immediate Attention

High-value claims and accounts approaching payer deadlines deserve special attention.

For example, an unresolved surgical claim may represent a larger outstanding balance than several routine office visits combined.

However, claim value is not the only consideration. A smaller claim approaching its final appeal deadline may require action first.

Billing teams should prioritize accounts based on financial value, deadline, reason for nonpayment, and likelihood of recovery.

Our Revenue Cycle Management Services describe how claim tracking, payment posting, and A/R follow-up work together to support practice collections.

Revenue Cycle Metrics to Monitor After a Billing Transition

Practice owners should not have to guess whether their new billing company is performing well.

A few clear financial indicators can show whether the transition is improving operations or creating new problems.

Claim Submission Lag: How many days pass between a completed patient encounter and the submission of its insurance claim?

First-Pass Acceptance Rate: What percentage of claims pass initial submission checks without being rejected?

Initial Claim Denial Rate: How many claims are denied after payer processing, and are the same problems occurring repeatedly?

Days in A/R: How long does outstanding reimbursement remain uncollected?

Old A/R Recovered: How much eligible historical revenue has actually been collected after the transition?

Payment Reconciliation: Do insurance deposits, remittance records, and posted payments match?

Unresolved Appeals: How many open appeals remain, who owns them, and which deadlines are approaching?

These numbers should be compared with the practice’s financial position before the transition.

A new billing partner should be able to explain not only what has improved, but also which outstanding issues still require attention.

Frequently Asked Questions About Switching Medical Billing Companies

Can I Change Medical Billing Companies Without Losing Outstanding Payments?

Yes. A properly planned transition can preserve access to outstanding claims and keep payment follow-up moving.

However, the practice must assign responsibility for old A/R, pending claims, appeals, and payment posting before the previous company stops working.

Changing billing vendors does not automatically cancel claims or prevent payers from making eligible payments.

Who Is Responsible for Claims Submitted by My Previous Billing Company?

Responsibility depends on the agreements between the practice and its billing vendors.

The outgoing company may continue working historical claims, the incoming company may take over, or both may divide the work.

The practice should document who is responsible for each unfinished account.

Can a New Billing Company Take Over Existing Appeals?

Yes, if the new company agrees to provide that service and receives the information and necessary authorization to continue the process.

It needs the original denial, previously submitted documentation, payer reference numbers, and remaining deadlines.

An appeal should not be restarted unnecessarily when a valid request is already pending.

Will Changing Billing Companies Affect Medicare or Insurance Enrollment?

Changing a billing service provider does not ordinarily change a physician’s underlying Medicare enrollment or insurance network participation.

However, the practice may need to update electronic claims submission arrangements, clearinghouse authorizations, ERA delivery settings, or other payer administrative records.

Those requirements should be verified before the old vendor’s access is removed.

How Long Does a Medical Billing Company Transition Take?

There is no single timeline that applies to every practice.

The time required depends on the number of providers, software systems, payer connections, outstanding claims, and historical A/R being transferred.

A small practice using the same billing platform may require a less complicated handoff than a multispecialty group migrating between systems.

The practice should agree on a realistic transition plan with clear milestones rather than assume that signing a new contract completes the process.

How Pro Medical Billing Solutions Helps Practices Transition

Switching medical billing companies should give your practice better control over its revenue, not leave it wondering who is managing unpaid claims.

Pro Medical Billing Solutions (PROMBS) supports healthcare providers with claim submission, coding coordination, denial management, payment posting, A/R follow-up, and financial reporting.

For practices considering a vendor change, the starting point is understanding what is working, where revenue is delayed, and which unfinished billing activities need attention.

Our team can help review billing workflows, identify outstanding claim problems, and establish responsibilities based on the services included in the new agreement.

Whether your practice is dealing with growing A/R, missing payment records, unresolved denials, or poor communication with its current vendor, a structured transition review can help make the next steps clearer.

Explore our Medical Billing Services and learn how PROMBS supports healthcare practices throughout the revenue cycle.

You can also learn more about hiring a medical billing company that prioritizes claim accountability, reporting transparency, and consistent follow-up.