Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

DR. NANCY M. MARX PH.D.
NPI 1700835923
Psychologist in San Mateo, CA

Active since May 06, 2006Opted out of Medicare · through Feb 29, 2028
155 BOVET RD, SUITE 404, SAN MATEO, CA 94402(650) 562-1904(650) 508-0353 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 09, 2026.

About Dr. Nancy M. Marx Ph.d. NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. NANCY M. MARX PH.D. (NPI 1700835923) is an individual psychologist in San Mateo, California, licensed in California (PSY17090) and active in the NPI registry since May 2006. She has opted out of Medicare through February 29, 2028 and remains eligible to order and refer.

NPPES Registry Identity

NPI1700835923
Entity TypeIndividualFemale
Primary Taxonomy103T00000X
Provider Legal NameDR. NANCY M. MARXCredential: PH.D.
Location Address155 BOVET RD, SUITE 404San Mateo, CA 94402-3108
Mailing Address155 Bovet Rd, Suite 404San Mateo, CA 94402-3108 · (650) 562-1904 · Fax (650) 508-0353
Fax(650) 508-0353
Sole ProprietorNo
Enumeration DateMay 6, 2006
Last NPPES UpdateJuly 13, 2026
NPI 1700835923 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

Primary SpecialtyPsychologistBehavioral Health & Social Service Providers
Taxonomy Code103T00000X
License Licensed in CA · PSY17090
Definition
A psychologist is an individual who is licensed to practice psychology which is defined as the observation, description, evaluation, interpretation, and modification of human behavior by the application of psychological principles, methods, and procedures, for the purpose of preventing or eliminating symptomatic, maladaptive, or undesired behavior and of enhancing interpersonal relationships, work and life adjustment, personal effectiveness, behavioral health, and mental health. The practice of psychology includes, but is not limited to, psychological testing and the evaluation or assessment of personal characteristics, such as intelligence, personality, abilities, interests, aptitudes, and neuropsychological functioning; counseling, psychoanalysis, psychotherapy, hypnosis, biofeedback, and behavior analysis and therapy; diagnosis and treatment of mental and emotional disorder or disability, alcoholism and substance abuse, disorders of habit or conduct, as well as of the psychological aspects of physical illness, accident, injury, or disability; and psycheducational evaluation, therapy, remediation, and consultation. Psychological services may be rendered to individuals, families, groups and the public.
155 BOVET RD, San Mateo, CA 94402

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

Opted out of Medicare

Dr. Nancy M. Marx Ph.d. has filed a Medicare opt-out affidavit. Services are provided under private contract between the provider and the patient, and are not billed to or reimbursed by Medicare. The opt-out is on file from February 28, 2016 through February 29, 2028.

Opt-Out Effective DateFebruary 28, 2016
Opt-Out In Effect ThroughFebruary 29, 2028Opt-out affidavits renew automatically every two years unless cancelled
Eligible to Order & Refer Part B Labs & Imaging Durable Medical Equipment Home Health Agency Power Mobility DevicesAn opted-out provider can still order and refer for Medicare patients in the categories marked above, even though their own services are not covered.

Other Providers at the Same Location NPPES 3

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

Psychologist (Clinical)
155 BOVET RD, SUITE 404
SAN MATEO, CA 94402
Psychologist (Clinical)
155 BOVET RD, SUITE 404
SAN MATEO, CA 94402
Psychologist (Clinical)
155 BOVET RD, SUITE 404
SAN MATEO, CA 94402

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 Nancy Marx's NPI number?

The NPI number for Nancy Marx is 1700835923. It was assigned to this individual provider in the NPPES registry on May 6, 2006.

Where is Nancy Marx located?

Nancy Marx practices at 155 Bovet Rd Suite 404, San Mateo, CA 94402. The listed phone number is (650) 562-1904.

What is Nancy Marx's specialty?

The primary specialty registered for this NPI is Psychologist with taxonomy code 103T00000X.

Is Nancy Marx enrolled in Medicare?

No. Nancy Marx has opted out of Medicare through February 29, 2028. Care is provided under private contracts, and Medicare does not pay for services furnished by providers who have opted out. The provider remains eligible to order and refer services for Medicare patients.

When was this NPI record last updated?

The NPPES record for Nancy Marx was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 35 days 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.