Grant David Williams, MD
Emergency Medicine Physician · San Marcos, TX
Grant David Williams, MD is an emergency medicine physician with a practice address in San Marcos, Texas, and NPI 1487697074, issued on Jun 13, 2006. Check the license (Texas M4656, as entered in NPPES) on the Texas Medical Board; the Medicare figures below come from public CMS files.
- Name
- Grant David Williams
- Credential
- MD
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- M4656 TX
Self-reported in NPPES; status is on the state search - Practice location
- 1301 Wonder World Dr, San Marcos, TX 78666
- Phone
- (512) 753-3796
- Enumerated
- Jun 13, 2006
- Record last updated
- Mar 25, 2008 (not updated in 18 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20190226001467); accepts Medicare assignment
- Medical or professional school
- University Of Texas Southwestern Medical School At Dallas, 2003
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 4,885 in Texas → Look up another NPI →
Also registered at 1301 Wonder World Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Raka Amin, MDInternal Medicine Physician1437576493
- Jose Ayala, MDInternal Medicine Physician1114960663
- Chad Benninghoff, NPFamily Nurse Practitioner1912256256
- Shyra BerishSpeech-Language Pathologist1235656364
- Jessica Best, MDEmergency Medicine Physician1679833354
Verify Grant David Williams in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersTexas Medical Board
Search for license M4656Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
55% fewer Medicare Part D claims than the average emergency medicine physician in 2024
101 Medicare Part D claims for 74 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D. 17 claims were for opioids.
Most prescribed
- Cephalexin11 claims
- Hydrocodone-Acetaminophen11 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).
Bills Medicare through one group practice
- Wake Forest Emergency ProvidersBoone, NC
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Grant David Williams among 4,885 emergency medicine physician records in Texas
Grant David Williams, MD is one of 4,885 emergency medicine physician records with a practice address in Texas. 83% 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 6% of them.
- NPI issued2006 · 6% of these records are older, 67% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 57% of these records are
- Graduated2003 · median 2013 among the 2,779 with a school on file
- Record last updated2008 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a Texas practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
11 emergency medicine physician records list a practice address in San Marcos
They are 11 of the 1,003 NPPES records with a practice address in San Marcos, and 4,885 emergency medicine physician records in Texas.
All 4,885 in Texas → Every provider in San Marcos → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Jessica Best, MDSan Marcos, TX 786661679833354
- Myla Canales, M.D.San Marcos, TX 786661376886317
- Curtis Grote, MDSan Marcos, TX 786661720078090
- Bradley LawingSan Marcos, TX 786661629411517
- Toan Leung, MDSan Marcos, TX 786661699726000
- Daniel Loisel, DOSan Marcos, TX 786661245220540
- Jose Pena, MDSan Marcos, TX 786661104817220
- Randolph Seybold, MDSan Marcos, TX 786661659361954
Common questions
What is Grant David Williams, MD's NPI number?
Grant David Williams, MD's National Provider Identifier (NPI) is 1487697074, issued on Jun 13, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Grant David Williams, MD located?
The NPPES record lists a practice address at 1301 Wonder World Dr, San Marcos, TX, 78666. Phone: (512) 753-3796. Providers update this record themselves, so call before visiting.
How can I verify Grant David Williams, MD's license?
NPPES lists Texas license number M4656, as entered by the provider. Search the Texas Medical Board at https://profile.tmb.state.tx.us/Search.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Grant David Williams, MD prescribe under Medicare Part D?
In 2024, Grant David Williams, MD had 101 Medicare Part D claims for 74 beneficiaries; the average among emergency medicine physician prescribers was 226. Part D covers Medicare prescriptions only.
What is Grant David Williams, 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.