Registry data as of Aug 27, 2026

Marissa Fox, MD

Internal Medicine Physician · Los Angeles, CA

Marissa Fox, MD is an internal medicine physician with a practice address in Los Angeles, California, and NPI 1356970883, issued on Apr 6, 2020. Check the license (California A178987, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, loaded Aug 27, 2026 · Medicare files 2023 and 2024 · method · Verify with CMS →

NPPES recordas of Aug 27, 2026
1356970883
Name
Marissa Fox
Credential
MD
Primary taxonomy
Internal Medicine Physician 207R00000X
License number
A178987 CA
Self-reported in NPPES; status is on the state search
Practice location
5901 W Olympic Blvd Ste 310, Los Angeles, CA 90036
Phone
(323) 215-1725
Enumerated
Apr 6, 2020
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). A record is not a license: verify it with the state board.
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Also registered at 5901 W Olympic Blvd Ste 310

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Caroline Belin, NP-CNurse Practitioner1447769971
  2. Matthew Diebler, AMFTMarriage & Family Therapist1104624139
  3. Wayne Ho, M.D.Internal Medicine Physician1477731867
  4. Kevin Rauchut, NP-CGerontology Nurse Practitioner1578084547
  5. Arthur Vermeulen, MDInternal Medicine Physician1598324055

Verify Marissa Fox in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license A178987
    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS, AOA, NCCPA, AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

Statewide context: the Medical Board of California reported 374 disciplinary actions in FY 2022-23. California discipline data →

5% fewer Medicare Part D claims than the average internal medicine physician in 2024

2,635 Medicare Part D claims for 219 beneficiaries, against an average of 2,785 among the 127,794 providers of this specialty who prescribed in Part D. Brand-name drugs were 28% of claims. 57 claims were for opioids.

  1. Marissa Fox2,635
  2. Specialty average2,785

Most prescribed

  1. Biktarvy162 claims
  2. Atorvastatin Calcium109 claims
  3. Gabapentin64 claims
  4. Losartan Potassium59 claims
  5. Omeprazole55 claims
  6. Metformin Hcl48 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: $2,515.31

99 payments, mostly food and beverage; the largest payer was ViiV Healthcare Company. The 65,274 providers of this specialty with any payment received $2,536.66 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.

  1. Marissa Fox$2,515.31
  2. Specialty average$2,536.66

Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.

1,665 internal medicine physician records list a Los Angeles practice address

They are 1,665 of the 69,537 NPPES records with a Los Angeles practice address, and 20,403 internal medicine physician records in California.

Other internal medicine physician records in California

  1. Jacob Aaron, MDSan Francisco, CA1407202518
  2. Alistair Aaronson, MDStanford, CA1457628760
  3. Jose Abad., MDSacramento, CA1144607219
  4. Donna Abare, MDOakland, CA1386722155
  5. Marce AbareScotts Valley, CA1457744708
  6. Samuel Abarte, M.D.Chula Vista, CA1578535498
  7. Alexander Abary, MDLong Beach, CA1104995919
  8. Luba Abascal, MDSan Francisco, CA1023180874
  9. Michael Abate, MDSacramento, CA1548248131
  10. Wali Abawi, D.O.Joshua Tree, CA1104362268

Common questions

What is Marissa Fox, MD's NPI number?

Marissa Fox, MD's National Provider Identifier (NPI) is 1356970883, issued on Apr 6, 2020. An NPI identifies a provider in billing; it is not a license.

Where is Marissa Fox, MD located?

The NPPES record lists a practice address at 5901 W Olympic Blvd Ste 310, Los Angeles, CA, 90036. Phone: (323) 215-1725. Providers update this record themselves, so call before visiting.

How can I verify Marissa Fox, MD's license?

NPPES lists California license number A178987, 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 Marissa Fox, MD prescribe under Medicare Part D?

In 2024, Marissa Fox, MD had 2,635 Medicare Part D claims for 219 beneficiaries; the average among internal medicine physician prescribers was 2,785. Part D covers Medicare prescriptions only.

Source: CMS National Plan and Provider Enumeration System (NPPES), loaded Aug 27, 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.

Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 27, 2026.