William Bayer, MD
Endocrinology, Diabetes & Metabolism · Carol Stream, ILNPI 1528162898
Payments from drug & device makers
What this record shows
This record is dominated by speaking fees: $60,016 of the $75,373 with a category attached, or 79.6%. 9 manufacturers reported payments, led by Novo Nordisk at 59.9% of the total. Reporting peaked in 2019 at $27,936 and has fallen 95.5% since, to $1,269 in 2025. Among endocrinology, diabetes & metabolism clinicians in IL with any reported payments, this total sits in the top 10% — high for the specialty, which is a reason to read the composition above rather than the number alone.
Across 223 payments — averaging $338.00 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Novo Nordisk$45K
- Lilly USA, LLC$13K
- AbbVie$9K
- Boehringer Ingelheim$7K
- Dexcom, Inc.$1K
- AstraZeneca$276
- plus $404 from 3 others
What the payments were for
- Consulting fees$2,9254%
- Speaking & faculty fees$60,01680%
- Travel & lodging$3,0594%
- Food & beverage$9,22612%
- Education$1470%
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| Novo Nordisk | 98 | $45,117 |
| Lilly USA, LLC | 41 | $12,543 |
| AbbVie | 25 | $8,574 |
| Boehringer Ingelheim | 33 | $7,264 |
| Dexcom, Inc. | 18 | $1,194 |
| AstraZeneca | 4 | $276 |
| Amgen | 2 | $228 |
| Xeris Pharmaceuticals, Inc. | 1 | $125 |
| Abbott | 1 | $50 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
- RYBELSUS$23,415
- JARDIANCE$17,719
- Ozempic$12,437
- Synthroid$5,558
- Tresiba$3,208
- Xultophy 100/3.6$2,217
- DEXCOM G6 TRANSMITTER$823
- MOUNJARO$352
- EVENITY$228
- Levemir$143
- Victoza$143
- GVOKE HYPOPEN$125
- ZEPBOUND$124
- Wegovy$124
- DEXCOM CGM$123
- FARXIGA$110
How this compares
$75,373 in reported general payments places this provider in the 90th percentile of 347 endocrinology, diabetes & metabolism providers in Illinois.
See all endocrinology, diabetes & metabolism providers in Illinois →
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| OzempicSemaglutide | 565 | $896,834 |
| JardianceEmpagliflozin | 198 | $284,103 |
| Tresiba Flextouch U-200Insulin Degludec | 67 | $205,171 |
| Tresiba Flextouch U-100Insulin Degludec | 149 | $157,007 |
| RybelsusSemaglutide | 68 | $104,457 |
| TrulicityDulaglutide | 72 | $101,616 |
| Toujeo SolostarInsulin Glargine,hum.Rec.Anlog | 40 | $55,224 |
| Fiasp FlextouchInsulin Aspart (Niacinamide) | 31 | $53,928 |
| Humalog Kwikpen U-100Insulin Lispro | 110 | $53,710 |
| JanuviaSitagliptin Phosphate | 31 | $50,818 |
| Toujeo Max SolostarInsulin Glargine,hum.Rec.Anlog | 20 | $44,518 |
| MounjaroTirzepatide | 27 | $39,226 |
| SynthroidLevothyroxine Sodium | 372 | $36,151 |
| Novolog FlexpenInsulin Aspart | 69 | $31,877 |
| FarxigaDapagliflozin Propanediol | 25 | $31,391 |
Paid to pharmacies, not to this prescriber.
Companies that both paid and supply prescribed drugs
These companies both reported payments to this provider and make drugs the provider prescribed under Medicare Part D in 2024. For most specialties this overlap is expected — a cardiologist who is paid by a cardiology drugmaker also treats heart disease. It is shown so the reader can see it, not because it implies anything on its own.
| Company | Paid to this provider | Part D cost of their drugs |
|---|---|---|
| Novo NordiskOzempic, Rybelsus, Novolog | $45,117 | $1,013,430655 claims |
| Boehringer IngelheimJardiance, Tradjenta | $7,264 | $310,626228 claims |
| Lilly USA, LLCTrulicity, Mounjaro, Humalog | $12,543 | $152,391130 claims |
| AbbVieSynthroid, Armour Thyroid | $8,574 | $37,614384 claims |
| AstraZenecaFarxiga | $276 | $31,39125 claims |
Reading this fairly. The Part D column is what drug plans and patients paid pharmacies — this provider received none of it, and it reflects how many patients they treat and what those drugs cost. Against peers, this provider's reported payments sit in the 90th percentile of 347 endocrinology, diabetes & metabolism providers in Illinois.
Other endocrinology, diabetes & metabolism in Carol Stream
- Wahid KassarChicago$884K
- Anthony PickLake Forest$665K
- Babak PazookiJoliet$582K
- Ammar BayrakdarEvergreen Park$517K
- George BakrisChicago$403K
- Terrence SwadeLombard$369K
- Wenyu HuangChicago$341K
- Liana BillingsSkokie$295K
- Daniel SoArlington Heights$283K
- Silvana PannainChicago$226K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.