ALEXANDER HALLAC MD
NPI 1386039998
Hospitalist in Greenwich, CT
About Alexander Hallac Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
ALEXANDER HALLAC MD (NPI 1386039998) is an individual hospitalist provider in Greenwich, Connecticut, licensed in Connecticut (64929) and active in the NPI registry since March 2015. He is enrolled in Medicare PECOS, is affiliated with White Plains Hospital Center, and is a graduate of Other (2015).
NPPES Registry Identity
Specialties & Licenses
Group Practice 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Alexander Hallac Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
4Medicare enrollment records show Alexander Hallac reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Greenwich, CT 06830
- Reassigned Medicare billing, Connecticut enrollment
- Medicare enrollment name: Northeast Medical Group Inc
- 1,824 clinicians in this Medicare group
White Plains, NY 10601
- Reassigned Medicare billing, New York enrollment
- 479 clinicians in this Medicare group
Concord, MA 01742
- Reassigned Medicare billing, Massachusetts enrollment
- 451 clinicians in this Medicare group
Burlington, MA 01805
- Reassigned Medicare billing, Massachusetts enrollment
- Also billed through NPI 1063447316 (Massachusetts)
- 1,574 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 4
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
White Plains Hospital Center
Acute Care Hospitals · White Plains, NYPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 06830 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
GREENWICH, CT 06830
GREENWICH, CT 06830
GREENWICH, CT 06830
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Alexander Hallac's NPI number?
The NPI number for Alexander Hallac is 1386039998. It was assigned to this individual provider in the NPPES registry on March 31, 2015.
Where is Alexander Hallac located?
Alexander Hallac practices at 5 Perryridge Rd, Greenwich, CT 06830. The listed phone number is (203) 863-3151.
What is Alexander Hallac's specialty?
The primary specialty registered for this NPI is Hospitalist with taxonomy code 208M00000X.
Is Alexander Hallac enrolled in Medicare?
Yes. Alexander Hallac is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Alexander Hallac's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Alexander Hallac reassigns Medicare benefits to 4 organizations: Mill Hill Medical Consultants Inc (Greenwich, CT), East Post Road Medical Services PC (White Plains, NY), Emerson Practice Associates, Inc. (Concord, MA) and Lahey Clinic, Inc. (Burlington, MA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Alexander Hallac's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Alexander Hallac accept?
Health plans from Taro Health list Alexander Hallac as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Alexander Hallac affiliated with any hospitals?
According to CMS data, Alexander Hallac is affiliated with White Plains Hospital Center.
When was this NPI record last updated?
The NPPES record for Alexander Hallac was last updated on July 24, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Alexander Hallac, MD · NPI 1386039998
Hospitalist physician in Greenwich, Connecticut. Individual provider, active in the CMS NPPES registry since March 31, 2015.
## Identity
- **NPI:** 1386039998 (Entity type: Individual)
- **Enumerated:** March 31, 2015
- **Primary specialty:** Hospitalist · taxonomy 208M00000X
- **State license:** 64929 (Connecticut)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 5 PERRYRIDGE RD, Greenwich, CT 06830-4697
- **Phone:** (203) 863-3151
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 4 organizations under Medicare reassignment (form CMS-855R): Mill Hill Medical Consultants Inc (NPI 1144230954, Greenwich, CT); East Post Road Medical Services PC (NPI 1841767274, White Plains, NY); Emerson Practice Associates, Inc. (NPI 1508020199, Concord, MA); Lahey Clinic, Inc. (NPI 1538194980, Burlington, MA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2015
## Record status
- **NPPES last updated:** July 24, 2024
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Source: [NPI Profile](https://npiprofile.com/npi/1386039998) · Data from the CMS NPPES public registry.