WILLIAM D. MOSIER, M.D., INC., A PROFESSIONAL MEDICAL CORPORATION
NPI 1003476508
Ophthalmology in Fullerton, CA
About William D. Mosier, M.d., Inc., A Professional Medical Corporation NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
WILLIAM D. MOSIER, M.D., INC., A PROFESSIONAL MEDICAL CORPORATION (NPI 1003476508) is a healthcare organization registered as an ophthalmology in Fullerton, California and active in the NPI registry since June 2019. The organization lists William D Mosier, Owner, as its authorized official.
NPPES Registry Identity
Specialties & Licenses
Group Practice 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
William D. Mosier, M.d., Inc., A Professional Medical Corporation is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Clinicians Billing Medicare Through This Organization
6Medicare enrollment records show 6 clinicians reassign Medicare billing to William D. Mosier, M.D., Inc., A Professional Medical Corporation, which bills Medicare for the services they deliver. Of these, 2 practice at this address. They are listed nearest first.
Clinicians, nearest first (6)
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is William D. Mosier, M.D., Inc., A Professional Medical Corporation's NPI number?
The NPI number for William D. Mosier, M.D., Inc., A Professional Medical Corporation is 1003476508. It was assigned to this organization in the NPPES registry on June 17, 2019.
Where is William D. Mosier, M.D., Inc., A Professional Medical Corporation located?
William D. Mosier, M.D., Inc., A Professional Medical Corporation is located at 265 Laguna Rd, Fullerton, CA 92835. The listed phone number is (714) 871-2570.
What is William D. Mosier, M.D., Inc., A Professional Medical Corporation's specialty?
The primary specialty registered for this NPI is Ophthalmology with taxonomy code 207W00000X.
Is William D. Mosier, M.D., Inc., A Professional Medical Corporation enrolled in Medicare?
Yes. William D. Mosier, M.D., Inc., A Professional Medical Corporation is registered in the Medicare PECOS enrollment system.
How many clinicians bill Medicare through William D. Mosier, M.D., Inc., A Professional Medical Corporation?
According to the CMS Revalidation Reassignment List (October 2026 release), 6 clinicians in 2 Medicare specialties reassign their Medicare billing to William D. Mosier, M.D., Inc., A Professional Medical Corporation. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. The largest specialties are Ophthalmology (5) and Optometry (1). Of these, 2 practice at this address. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
What insurance does William D. Mosier, M.D., Inc., A Professional Medical Corporation accept?
Health plans from Anthem Blue Cross and Blue Shield, Blue Cross and Blue Shield of Montana, Blue Cross and Blue Shield of Oklahoma, Blue Cross and Blue Shield of Texas and BlueCross BlueShield of Tennessee list William D. Mosier, M.D., Inc., A Professional Medical Corporation as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
When was this NPI record last updated?
The NPPES record for William D. Mosier, M.D., Inc., A Professional Medical Corporation was last updated on November 2, 2023. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# William D. Mosier, M.d., Inc., A Professional Medical Corporation · NPI 1003476508
Ophthalmology organization in Fullerton, California. Organization record, active in the CMS NPPES registry since June 17, 2019.
## Identity
- **NPI:** 1003476508 (Entity type: Organization)
- **Enumerated:** June 17, 2019
- **Primary specialty:** Ophthalmology · taxonomy 207W00000X
- **Organization subpart:** No
- **Authorized official:** William Mosier, OWNER
## Practice location
- **Address:** 265 LAGUNA RD, Fullerton, CA 92835-2515
- **Phone:** (714) 871-2570 · **Fax:** (714) 441-2020
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Clinicians billing through this organization:** 6 clinicians in 2 Medicare specialties reassign Medicare billing to this organization (form CMS-855R); largest: Ophthalmology (5), Optometry (1); 2 practice at this address · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** November 2, 2023
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Source: [NPI Profile](https://npiprofile.com/npi/1003476508) · Data from the CMS NPPES public registry.