William Peter Sim, M.D.
Internal Medicine Physician · Cerritos, CA
William Peter Sim, M.D. is an internal medicine physician with a practice address in Cerritos, California, and NPI 1902166531, issued on May 16, 2012. Check the license (California A130389, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William Peter Sim
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A130389 CA
Self-reported in NPPES; status is on the state search - Practice location
- 10820 183RD St, Cerritos, CA 90703
- Phone
- (562) 653-5000
- Enumerated
- May 16, 2012
- Record last updated
- Dec 10, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20151202002112); accepts Medicare assignment
- Medical or professional school
- Un Of California, Irvine, College Of Medicine, 2012
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 10820 183RD St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Joyce Hatanaka FongPharmacist1801335302
- Kerry Kawano, R.PH.Pharmacist1407395908
- Lynda Ngo, M.D.Internal Medicine Physician1053732636
- Denise Park, MDInternal Medicine Physician1518015338
- Mayur PatelPharmacist1265971923
Verify William Peter Sim in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A130389Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
79% more Medicare Part D claims than the average internal medicine physician in 2024
5,679 Medicare Part D claims for 682 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 10% of claims. 145 claims were for opioids.
Most prescribed
- Atorvastatin Calcium467 claims
- Amlodipine Besylate297 claims
- Losartan Potassium280 claims
- Lisinopril259 claims
- Rosuvastatin Calcium203 claims
- Simvastatin161 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $18.23
1 payment: food and beverage; the largest payer was AstraZeneca Pharmaceuticals LP. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupBellflower, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William Peter Sim among 17,696 internal medicine physician records in California
William Peter Sim, M.D. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2012, is newer than 68% of them.
- NPI issued2012 · 68% of these records are older, 29% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2012 · median 2004 among the 11,065 with a school on file
- Record last updated2021 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
23 internal medicine physician records list a practice address in Cerritos
They are 23 of the 1,842 NPPES records with a practice address in Cerritos, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Cerritos → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Noel Bakh, MDCerritos, CA 907031366682742
- Ki Che, M.D.Cerritos, CA 907031922139906
- Mark Chung, MDCerritos, CA 907031740290378
- Robert Collen, M.D.Cerritos, CA 907031538267125
- Pinal Doshi, M.D.Cerritos, CA 907031326062712
- John Ford, M.D.Cerritos, CA 907031922071596
- Mary Eppie Gonzales, M.D.Cerritos, CA 907031649231739
- Kasey Kim, MDCerritos, CA 907031992715437
Common questions
What is William Peter Sim, M.D.'s NPI number?
William Peter Sim, M.D.'s National Provider Identifier (NPI) is 1902166531, issued on May 16, 2012. An NPI identifies a provider in billing; it is not a license.
Where is William Peter Sim, M.D. located?
The NPPES record lists a practice address at 10820 183RD St, Cerritos, CA, 90703. Phone: (562) 653-5000. Providers update this record themselves, so call before visiting.
How can I verify William Peter Sim, M.D.'s license?
NPPES lists California license number A130389, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William Peter Sim, M.D. prescribe under Medicare Part D?
In 2024, William Peter Sim, M.D. had 5,679 Medicare Part D claims for 682 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.