Healthcare IT · Revenue cycle automation
LunaBill
AI voice agents that call insurance companies on a hospital's behalf, chasing unpaid claims the way a biller would, around the clock. Backed by Y Combinator, with one named customer and a funding picture still hard to pin down.
Listening to Luna
LunaBill's homepage offers a short recording: Luna on hold with a payer, working an interactive voice tree, then getting a live representative on the line. The company says the clip contains no protected health information. The pitch is that a claim which would have sat in a biller's queue gets worked the moment it is eligible instead.
The company's own account of how a claim moves: it sits unpaid past the payer's clock, Luna checks the payer portal first, and if stalled Luna calls the payer and gets it reprocessed or escalated with a reference number. If denied, Luna drafts and files the appeal. Every action, the company says, is written back into the EHR.
The problem it is aimed at
Healthcare billing teams spend a large share of the day on the phone with insurers, checking on claims gone unanswered. In its Y Combinator profile, LunaBill puts the figure at 80 percent of a billing team's daily workload, with each call averaging 30 minutes. Its later launch post, on the same YC page, revises call length to 25 minutes and adds that U.S. billing teams make tens of millions of such calls weekly, chasing part of the 260 billion dollars in denied or delayed payments hospitals see each year.
LunaBill's about page cites two outside figures to make the same point: reworking a denied commercial claim costs 63.76 dollars on average per Premier Inc, or 43.84 dollars across all payers, and 65 percent of denied claims are never reworked, a figure it attributes to the Change Healthcare Revenue Cycle Denials Index. This review has not independently checked either underlying report.
The company's framing, stated by CEO Suhail Parry on the site, is that this is an infrastructure gap rather than a hiring problem: a revenue cycle team should not need to keep growing headcount just to keep more people on hold.
Three founders, one prior revenue cycle job
LunaBill's about page describes Suhail Parry as a McGill graduate and two time founder: a founding engineer at Knowext, building AI automation for hospital systems, then running billing operations at Mediregi, an RCM company the page says serves 200 plus healthcare clients. That is more specific than LunaBill's Y Combinator page, which credits him with "operating a medical billing company with 200+ healthcare clients," language that could be read as founding one rather than working inside an existing firm. The two are not necessarily in conflict, but they are not identical.
David Day, LunaBill's CTO, founded Skiesoft, called one of Taiwan's largest AI medical scribe companies, used by "thousands" of healthcare professionals in the Y Combinator text and by 120,000 users in the company's launch post, a jump this review could not reconcile. He later worked as a data scientist at UCSF, building models to audit medical coding accuracy, per both the YC profile and the about page.
Yash Raj, also referred to as Yash Raj Singh Thakur on LinkedIn and in a Y Combinator post, is described as a researcher across several hospital systems including Mayo Clinic, and as having built AI consumer apps with more than 10,000 users. No independent profile of his Mayo Clinic research was found in this review.
The three say they met at the Berkeley AI Hackathon, building an AI nurse, and teamed up months later around the insurance call problem they had each lived through.
From hackathon to a hospital's books
LunaBill's Y Combinator page preserves two versions of its own numbers. The earlier text, matching this review's records file, says that since a July launch the company reached 764,000 dollars in contracted annual recurring revenue, of which 428,000 was already live, the rest due by January 2026, with a tenfold increase in claims followed up per biller in the first week, a 100 percent pilot to paying conversion rate, and 50,000 plus calls automated. That version names UC health systems, Mayo Clinic and Experian Health as partners.
The launch post that now sits below it, tied to the public Launch YC listing, updates several figures: 60,000 plus calls automated, more than 20,000 biller hours saved, more than 30 million dollars recovered, and billers completing more than 300 claim follow ups a day, up from about 25. That later text drops the named partners for "top healthcare systems" and "three of the biggest enterprise billing companies," unnamed.
LunaBill's site now names one customer directly: Nutex Health, a 24 campus U.S. health system with a revenue cycle team of more than 60 people. The company says LunaBill worked more than 32 million dollars of AR there in 30 days with zero added headcount, that days in AR on claims aged past 60 days fell from 45 to 7, and that fully loaded cost per claim dropped from 22.28 to 2.00 dollars. LunaBill appears in the portfolios of two backers, Y Combinator and Founders, Inc, whose site lists a 2024 founding date, a year earlier than the 2025 on LunaBill's YC profile.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Y Combinator batch | Listed on YC's own site as Fall 2025 (F25), San Francisco, team size 4, Aaron Epstein primary partner. A YC branded LinkedIn post also calls it "LunaBill (YC F25)." | Public record |
| Founders, Inc. portfolio | Listed on the Founders, Inc. site as a portfolio company, founded 2024, team size 3. | Public record |
| Founding year | 2025 on LunaBill's Y Combinator profile; 2024 on the Founders, Inc. portfolio page and on PitchBook's company profile. | Differs across sources |
| Team size | 4 per Y Combinator, 3 per Founders, Inc, 5 per PitchBook. | Differs across sources |
| Named customer, Nutex Health | 32 million dollars plus of AR worked in 30 days, zero added headcount, days in AR down from 45 to 7, cost per claim down from 22.28 to 2.00 dollars. | Company-stated |
| Named partners UC health systems, Mayo Clinic, Experian Health | Named in the earlier YC profile text and a directory writeup drawn from it. Later launch text on the same page, and the current site, name only unnamed "top healthcare systems" and RCM firms. | Not confirmed independently |
| SOC 2 Type II and HIPAA | Company says it is HIPAA compliant, signs a BAA in under a day, and is SOC 2 Type II certified, with a trust center at trust.lunabill.com. No certificate was reviewed for this profile. | Company-stated |
| EHR and clearinghouse integrations | The company lists Epic, Cerner, GoRev, Waystar and Availity as systems it plugs into. | Company-stated |
| Call and revenue figures over time | 50,000+ calls and 764,000 dollars contracted ARR in the earlier text; 60,000+ calls, 30 million dollars plus recovered, and 90,000+ monthly payer interactions portfolio-wide later. | Company-stated |
Read plainly: the accelerator relationships and the company's changing set of numbers are on the record. The commercial claims, including the named customer, the certifications and the integrations, all come from LunaBill itself. No independent confirmation of any of them was found.
What to watch
- Whether Mayo Clinic, Experian Health or the UC health systems named earlier reappear, are confirmed independently, or are dropped for good.
- Independent confirmation of Nutex Health as a customer, or of the AR and cost per claim figures reported for it.
- Whether the SOC 2 Type II claim is confirmed by a published attestation.
- Which founding year and team size the company settles on across its own materials.
In their words
“This is an infrastructure problem, not a staffing problem. The revenue cycle shouldn’t require an army of people on hold.”
Suhail Parry, cofounder and CEO, lunabill.com · Company-stated
“Every week, U.S. healthcare billing teams make tens of millions of calls to insurance companies to get claims paid.”
Suhail Parry, David Day and Yash Raj, Launch YC post, 2025 · Company-stated
“We first met at the Berkeley AI Hackathon, where we built an AI nurse. A few months later, we teamed up to tackle the biggest operational pain point we’d all lived through: insurance phone calls.”
Suhail Parry, David Day and Yash Raj, Launch YC post, 2025 · Company-stated
“A McGill graduate and two-time founder who has spent his career inside the revenue cycle.”
LunaBill about page, on Suhail Parry · Company-stated
“Founded Skiesoft, one of Taiwan’s largest AI medical scribe companies, used by thousands of healthcare professionals.”
LunaBill about page, on David Day · Company-stated
“At Nutex Health, a 24 campus U.S. health system, LunaBill worked $32M+ of AR in 30 days with zero added headcount. Days in AR on 60+ day commercial claims fell from 45 to 7, and fully loaded cost per claim dropped from $22.28 to $2.00.”
LunaBill FAQ, lunabill.com · Company-stated
“LunaBill builds AI-powered voice callers that automate insurance claim follow-ups for healthcare billing teams. Their AI agents handle claim-status checks, appeals, and reprocessing calls, scaling like a full call center without the headcount.”
All Health Tech, roundup of the Y Combinator Fall 2025 healthtech batch, November 2025 · Independent
Related companies
Sources
- Public recordLunaBill company profile and Launch YC post
- Public recordLunaBill portfolio listing
- Public recordSuhail Parry founder page
- Independent10 healthtech startups in Y Combinator's Fall 2025 batch (YC F25)
- IndependentLunaBill: AI call center for healthcare billing teams
- AggregatorHow LunaBill is Transforming Healthcare Billing with AI
- AggregatorLunaBill Secures $100K Seed Round
- AggregatorLunabill company profile
- AggregatorLunaBill company page
- AggregatorSuhail Parry profile
- CompanyLunaBill homepage
- CompanyLunaBill about page
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
