Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

William Chunghun Sim, MD

Individual provider Internal Medicine Physician · NPI 1437256906

William Chunghun Sim, MD practises Internal Medicine in Downey, California. Graduated from Stanford University School of Medicine in 1990, 36 years ago. Practices with Frischer Medical Group Inc, a 4-clinician group, accepts Medicare assignment and offers telehealth. Licensed in California.

Years since qualifying
36
Trained at
Stanford University School of Medicine
Licensed in
CA
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

11480 Brookshire Ave 200
Downey, CA 90241-9998 Not confirmed with CMS for 14 years — call before visiting
Phone: (562) 806-0874
Fax: (562) 927-4801
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence G72353 (CA)

Record details

NPI number1437256906
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedSeptember 19, 2006
Last updated in NPPESDecember 20, 2011

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolSTANFORD UNIVERSITY SCHOOL OF MEDICINE
Graduated 1990 (36 years in practice)
Group practice Frischer Medical Group Inc — 4 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients787
Services billed 5,946 a service is one billed item, such as a visit, a test or a procedure
Average patient age80

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $1,982 94 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Frischer Medical Group Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice.

Other providers in Downey