William Sim, M.D.
NPI 1902166531 · Internal Medicine Physician · Cerritos, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Sim, M.D. is a Internal Medicine Physician provider in Cerritos, CA (NPI 1902166531).
Provider details
- NPI number
- 1902166531
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Student, Health Care
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
14 yrs in NPPES registry
- Profile completeness33% of score
83% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 94 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 467 | 165 |
| Amlodipine Besylate | 297 | 116 |
| Losartan Potassium | 280 | 95 |
| Lisinopril | 259 | 87 |
| Rosuvastatin Calcium | 203 | 73 |
| Simvastatin | 161 | 54 |
| Levothyroxine Sodium |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$18 across 1 record (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2012-05-16
- Last updated
- 2021-12-10
- Certified
- 2021-12-07
Frequently asked questions
- What is William Sim's NPI number?
- William Sim's National Provider Identifier (NPI) is 1902166531, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Sim's specialty?
- William Sim is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Sim located?
- William Sim's practice location on file with NPPES is 10820 183rd St, Cerritos, CA 90703-8013.
- What is William Sim's phone number?
- The practice phone number listed in the NPPES registry for William Sim is (562) 653-5000.
- Does William Sim accept Medicare?
- William Sim is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Sim's NPI active?
- Yes — William Sim's NPI (1902166531) is active in the NPPES registry as of the last update on 2021-12-10.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.