NPI registry status
Active
2026 NPPES data Hematology & Oncology Physician NPI 1689779209 MD
Verify on CMS → William Bonis, MD
Hematology & Oncology Physician in Chico, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 11,530 in Hematology & Oncology Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
421
Medicare Part D claims · 115 beneficiaries · Hematology & Oncology Physician avg: 885
Generic prescribing
80%
generic claims · 20% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$416.33
3 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2024
What the federal data shows
William Bonis, MD filed 421 Medicare Part D claims in 2024 as a Hematology & Oncology Physician in Chico, California, prescribing 80% generic.
- 421
- Part D claims, 2024
- 80%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥61st
- pct by Part D claim volume (lower-bound band)
Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) - no proprietary rating or editorial opinion is applied.
Federal trust snapshot
What official records show about William Bonis, MD
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1689779209), first enumerated 09/14/2006.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 421 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
1 CMS Care Compare hospital affiliation on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- Reported
Industry payment transparency
$416.33 in reported industry payments (3 transfers) in 2024 under the federal Sunshine Act — disclosed transfers of value, not a quality rating.
Source: CMS Open Payments
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not William Bonis, MD's individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1689779209 · Hematology & Oncology Physician
NPI-10 · ENUM-LEGACY · TAX-MID · RX-LIGHT · BOOK-LIGHT · PHOTO-ENUM
- NPI-10 1689779209
- ENUM-LEGACY 2006
- TAX-MID 12K Hematology &
- RX-LIGHT 421
- BOOK-LIGHT 1,306 in California
- PHOTO-ENUM Robert Bigler, M.D · 2006
William Bonis, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
421 ≥ 61st percentile 61% of 1,416,883 prescribers are in lower value bands
Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
William Bonis, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about William Bonis, MD?
Quality data not reportedPrimary specialty
Hematology & Oncology Physician
Medicare Part D claims
421 52% vs specialty avg
Specialty distribution in California
How Hematology & Oncology Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Hematology & Oncology Physician. Verify directly:
How MIPS and board certification work
The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).
Practice Address
Provider Details
| NPI | 1689779209 |
|---|---|
| Specialty | Hematology & Oncology Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 09/14/2006 |
Hospital and facility affiliations
Facilities where William Bonis, MD bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.
Marshall Medical Center
★★★★☆ 4/5
Cameron Park, CA
Acute Care Hospitals
CMS CCN: 050254
Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for William Bonis, MD. Source: openpaymentsdata.cms.gov.
Total received
$416
Largest payer
SOBI, INC
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
License & disciplinary context - California MBC 2023 annual report
Aggregate state board data only, NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 - they are NOT specific to William Bonis, MD. To verify William Bonis, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases
MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.
Brand vs generic prescribing mix · Typical
William Bonis, MD - brand share 20.0%
Hematology & Oncology Physician average
20% brand-name claims vs 80% generic, on 421 2024 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2024.
421
Total Claims
$1.2M
Total Drug Cost
115
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 534.1
- Total Day Supply
- 13,459
- Brand vs Generic
- 20% brand / 80% generic
- Brand Drug Cost
- $1.1M
- Generic Drug Cost
- $84K
- Opioid Claims
- 25 (5.9% rate)
- Antibiotic Claims
- 15
Patient Demographics
- Average Patient Age
- 73.5 years
- Avg HCC Risk Score
- 2.15
- Gender Split
- 63% female / 37% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What William Bonis, MD prescribes most
Top Medicare Part D drugs by claim count, 2024
- Anastrozole
Anastrozole
35 claims
- Ondansetron Hcl
Ondansetron Hcl
33 claims
- Tamoxifen Citrate
Tamoxifen Citrate
30 claims
- Prednisone
Prednisone
25 claims
- Xtandi
Xtandi
24 claims
- Prochlorperazine M…
Prochlorperazine Maleate
19 claims
- Dexamethasone
Dexamethasone
18 claims
- Exemestane
Exemestane
14 claims
| Drug | Claims |
|---|---|
| Anastrozole | 35 |
| Ondansetron Hcl | 33 |
| Tamoxifen Citrate | 30 |
| Prednisone | 25 |
| Xtandi Enzalutamide | 24 |
| Prochlorperazine Maleate | 19 |
| Dexamethasone | 18 |
| Exemestane | 14 |
| Abiraterone Acetate | 12 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Hematology & Oncology Physician Overview
How William Bonis, MD fits within the Hematology & Oncology Physician landscape nationally.
11,530
Hematology & Oncology Physician Providers in US
54
States with Hematology & Oncology Physician
885
Avg Claims per Provider
William Bonis, MD's 421 claims are below the specialty average of 885.
Nationwide Hematology & Oncology Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Bonis, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2006)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Hematology & Oncology Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Bonis.
One of 1,306 Hematology & Oncology Physician providers enrolled in California, 5 are shown here.
Dr. Mark Abate
M.D.
Santa Barbara, CA
Dr. Iman Abdalla
MD
Los Angeles, CA
Dr. Nihal Abdulla
MD
Los Alamitos, CA
Dr. Oyewale Abidoye
M.D.
La Jolla, CA
Dr. Mohamad Adada
M.D., PHD
Roseville, CA
Compare Hematology & Oncology Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is William Bonis, MD's specialty? ▼
William Bonis, MD specializes in Hematology & Oncology Physician and practices in Chico, California. Credentials: MD.
How much does William Bonis, MD prescribe under Medicare Part D? ▼
In 2024, William Bonis, MD wrote 421 Medicare Part D claims totaling $1.2M in drug costs for 115 beneficiaries.
Where is William Bonis, MD located? ▼
William Bonis, MD is located at 265 COHASSET RD, Chico, CA, 95926. Phone: (530) 332-3890.
What is William Bonis, MD's NPI number? ▼
William Bonis, MD's National Provider Identifier (NPI) is 1689779209, issued on 09/14/2006.
Does William Bonis, MD prescribe more brand-name or generic drugs? ▼
William Bonis, MD's prescribing is 20% brand-name and 80% generic drugs by claim count, with $1.1M in brand drug costs.
Does William Bonis, MD prescribe opioids? ▼
Yes, William Bonis, MD had 25 opioid claims in 2024 with an opioid prescribing rate of 5.9%.
How many Hematology & Oncology Physician providers are there in the US? ▼
There are 11,530 Hematology & Oncology Physician providers across 54 states in the US. The average Hematology & Oncology Physician provider writes 885 Medicare Part D claims per year.
What drugs does William Bonis, MD prescribe most often? ▼
Based on 2024 Medicare Part D data, William Bonis, MD's most frequently prescribed drugs include Anastrozole, Ondansetron Hcl, Tamoxifen Citrate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Bonis, MD accept Medicare? ▼
William Bonis, MD appears in CMS Medicare data with 421 Part D claims and 115 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Bonis, MD's credentials? ▼
William Bonis, MD's NPI is 1689779209 with credentials MD. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.
Data Sources
View source datasets and methodology notes
- Provider Directory
- CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
- Specialty Classification
- NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
- Prescribing Data
- CMS Medicare Part D Prescriber Public Use File (2024). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
- Limitations
- Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.
See our complete data methodology for details on how we collect and process government data.
Data as of August 2026 (NPPES) / 2024 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).
Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology
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 August 2026.