our story
The billing partner who actually knows behavioral health
IOU Billing was founded by Carolyn Reidy, CMRS — who started inside the behavioral health field, not the billing industry. That difference shows up in every claim we file.
how it started
From the mental health field to your billing partner
Carolyn Reidy began her career in behavioral health in 1994, at one of the Hudson Valley’s largest outpatient mental health facilities. It was there — inside the clinical world, not a billing company — that she built her foundation in insurance billing, reimbursement, provider operations, and the day-to-day financial realities providers face. She saw firsthand how much of a practice’s survival depends on claims getting paid, and how often they didn’t.
The relationships she formed in those early years became the foundation of her career. Many of the professionals she worked with decades ago went on to advance, change organizations, and open their own practices — and they stayed in touch. As they established private practices, many turned to Carolyn to help them set up billing operations, navigate insurers, secure credentialing and payer enrollments, and build the systems a financially healthy practice needs.
In 2003, she founded IOU Billing with a different vision: not a company that simply submits claims and waits, but a knowledgeable, accessible partner who understands the entire revenue cycle and the reality of running a practice. More than three decades into her career in medical billing, that’s still exactly what IOU Billing is.
WHy we are different
Behavioral health billing is more than submitting claims
IOU Billing has experience across many areas of healthcare, but its specialty is Mental Health and Substance Use Disorder services — and Carolyn’s behavioral health experience goes all the way back to 1994. That depth matters, because behavioral billing carries complexities most general billers never touch:
Authorizations and payer-specific requirements
Requirements that vary by plan and by service.
Credentialing and provider enrollment
Across multiple payers, start to finish
Claims processing, denials, and appeals
Worked through to resolution, not filed and forgotten.
Accounts receivable and collections
Patient statements, follow-up, and aging kept under control.
When a claim isn’t paid correctly, the real work is asking why — then following the issue through to resolution. Carolyn’s team looks at the entire revenue cycle to find where revenue is being delayed or lost, rather than filing a claim and hoping.
Direct payer experience
We’ve worked inside the payers you bill
This is what sets IOU Billing apart from the national platforms. The team has developed extensive, direct experience with Carelon Behavioral Health, Maryland Medicaid, and Beacon Health Strategies — and, notably, IOU Billing has worked directly for Maryland Medicaid.
Carelon Behavioral Health
Maryland Medicaid
Beacon Health Strategies
That firsthand knowledge of payer processes, authorization rules, behavioral health reimbursement, and claims handling means the team knows how these payers actually operate — not just how the manual says they should. Combined with more than three decades of behavioral healthcare experience, it gives IOU Billing a perspective that goes well beyond routine claim submission: how to investigate a problem, talk to a payer, and drive it to resolution.
what we stand for
Not a platform. Not offshore. A partner.
We answer the phone.
Responsive, US-based, and genuinely invested in your business — you get people, not a ticket queue. Despite the company’s growth, Carolyn stays personally involved and accessible.
We know your state.
Reimbursement isn’t one-size-fits-all. Requirements shift by state, payer, and provider type — and we learn a state’s rules before we bill a single claim in it.
We treat your revenue like ours.
Behind every unpaid claim, denial, or credentialing delay is revenue a provider has already earned. Claims are worked daily, denials appealed, nothing left to age out.
where we work
National experience, state-level expertise
IOU Billing works with practices across the country. We work across all 50 states, including California, Colorado, Florida, Louisiana, Maryland, Massachusetts, Mississippi, New Jersey, New Mexico, Nevada, Texas, and Virginia. Working across markets has given the team real command of the differences among state Medicaid programs, managed care organizations, Medicare, commercial carriers, and behavioral health networks — from authorization requirements to reimbursement guidelines.
Alabama, California, Colorado, Delaware, Florida, Illinois, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Nevada, New Jersey, New Mexico, New York, North Carolina, Ohio, Texas, Virginia, and Washington DC.
25+ Years in Business
We Can Work In All 50 States
CMRS Certified
All Clearinghouses & EHR
the difference
We treat your business like it’s our own
Carolyn Reidy takes that phrase literally. She answers the phone. She responds to questions. She gets involved when there’s a problem, and she stays with it until it’s resolved. Providers aren’t account numbers — if there’s an issue, she wants to know about it.
Some of Carolyn’s professional relationships span more than 30 years, continuing as providers changed organizations, opened practices, and grew their operations. For many longtime clients, she’s more than the owner of their billing company — she’s a trusted advisor and an extension of their practice.
“When providers start with us, they never leave.”
carolyn reidy, cmrs — founder, IOU Billing
Carolyn’s philosophy: let providers focus on caring for their patients, while IOU Billing protects their revenue, navigates the insurers, and makes sure they’re paid for the work they’ve already done.
beyond the office
Beyond IOU Billing
Outside of work, Carolyn enjoys cooking, entertaining friends and family, and spending time with her three English bulldogs — Winston, Bentley, and Lily. The people who know her see the same qualities in both parts of her life: she likes bringing people together, solving problems, and building relationships that last.
Let’s talk about your practice.