William Chunghun Sim, MD
Internal Medicine Physician · Downey, CA
William Chunghun Sim, MD is an internal medicine physician with a practice address in Downey, California, and NPI 1437256906, issued on Sep 19, 2006. Check the license (California G72353, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- William Chunghun Sim
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G72353 CA
Self-reported in NPPES; status is on the state search - Practice location
- 11480 Brookshire Ave, Downey, CA 90241
- Phone
- (562) 806-0874
- Enumerated
- Sep 19, 2006
- Record last updated
- Dec 20, 2011 (not updated in 15 years: call before relying on the address or phone)
- Fax
- (562) 927-4801
- Medicaid ID
- 00G723520 CA
- Medicare enrollment
- Enrolled (PECOS I20100311000876); accepts Medicare assignment
- Medical or professional school
- Stanford University School Of Medicine, 1990
- 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 11480 Brookshire Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify William Chunghun Sim in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G72353Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
12.1 times the Medicare Part D claims of the average internal medicine physician in 2024
38,470 Medicare Part D claims for 1,252 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 14% of claims. 325 claims were for opioids.
Most prescribed
- Atorvastatin Calcium2,063 claims
- Losartan Potassium1,669 claims
- Amlodipine Besylate1,383 claims
- Metformin Hcl1,224 claims
- Levothyroxine Sodium1,215 claims
- Metoprolol Succinate1,005 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.
No measured MIPS final score for 2023
CMS assigned the neutral MIPS final score of 75 without scoring Quality, Cost, Promoting Interoperability or Improvement Activities. It is an administrative threshold, so PlainDoctor does not compare it with measured clinicians.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Industry payments in 2024: $1,888.70
88 payments; by number, the most common kind was food and beverage; the largest payer was Lilly USA, LLC. 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
- Frischer Medical Group IncDowney, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
William Chunghun Sim among 17,696 internal medicine physician records in California
William Chunghun Sim, MD 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 2006, is newer than 5% of them.
- NPI issued2006 · 5% of these records are older, 56% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1990 · median 2004 among the 11,065 with a school on file
- Record last updated2011 · 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).
114 internal medicine physician records list a practice address in Downey
They are 114 of the 3,607 NPPES records with a practice address in Downey, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Downey → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Nazar Al-Bussam, MDDowney, CA 902411003999145
- Domingo Barrientos, M.D.Downey, CA 902411184685281
- Arthur Carrasco, M.D.Downey, CA 902411588601595
- Shahryar Davari, MDDowney, CA 902411346244373
- Henry Do, M.D.Downey, CA 902411538115290
- Alan Frischer, M.D.Downey, CA 902411982701454
- Narayana Gunda, M.D.Downey, CA 902411720026271
- Vinod Patel, M.D.Downey, CA 902411043226756
Common questions
What is William Chunghun Sim, MD's NPI number?
William Chunghun Sim, MD's National Provider Identifier (NPI) is 1437256906, issued on Sep 19, 2006. An NPI identifies a provider in billing; it is not a license.
Where is William Chunghun Sim, MD located?
The NPPES record lists a practice address at 11480 Brookshire Ave, Downey, CA, 90241. Phone: (562) 806-0874. Providers update this record themselves, so call before visiting.
How can I verify William Chunghun Sim, MD's license?
NPPES lists California license number G72353, 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 Chunghun Sim, MD prescribe under Medicare Part D?
In 2024, William Chunghun Sim, MD had 38,470 Medicare Part D claims for 1,252 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
What is William Chunghun Sim, MD's MIPS final score?
CMS assigned the neutral MIPS final score of 75 for 2023 without scoring any category, so it is not a measured result.
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.