Atty. Marion C. Leydier

Atty. Marion C. Leydier

Marion C. Leydier is a lawyer practicing insurance, financial services, capital markets and 4 other areas of law.

New York New York 24 yrs experience 24 year
Call (516) 689-0094 Book Appointment

Profile Summary

About Marion C. Leydier at a glance

Marion C. Leydier is a Partner based in New York, New York, practicing at Sullivan And Cromwell Llp. They have 24+ years of legal experience, licensed to practice since 2002. Their practice focuses on business, m&a, securities, consumer, and insurance. Admitted to practice in New York (2002). Educated at Columbia Law School (J.D., 2001) and E.S.S.E.C., Paris (M.B.A. Université, 1997). Serands clients in New York, NY and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

  • Marion C. Leydier is a lawyer practicing insurance, financial services, capital markets and 4 other areas of law
  • Marion received a M.B.A. degree from E.S.S.E.C., Paris in 1997, and has been licensed for 24 years
  • Marion practices at Sullivan & Cromwell LLP in New York, NY

Practice Areas Explained

Marion C. Leydier's Areas of Practice

Each practice area below reflects the types of cases Marion C. Leydier handles, with a brief overview of what that area of law covers.

Business & Corporate Law

Business attorneys advise founders and growing companies on entity formation, contracts, financing, M&A, and dispute resolution.

Marion C. Leydier is one of 501,317 business attorneys indexed nationally. Browse business attorneys in New York →

Mergers & Acquisitions

Marion C. Leydier is one of 49,731 m&a attorneys indexed nationally. Browse m&a attorneys in New York →

Securities Law

Marion C. Leydier is one of 64,529 securities attorneys indexed nationally. Browse securities attorneys in New York →

Consumer Protection

Consumer protection attorneys for fraud, lemon law, debt harassment, and deceptive trade practices.

Marion C. Leydier is one of 50,607 consumer attorneys indexed nationally. Browse consumer attorneys in New York →

Insurance Law

Insurance attorneys for coverage disputes, bad faith claims, denied claims, and policy disputes.

Marion C. Leydier is one of 121,912 insurance attorneys indexed nationally. Browse insurance attorneys in New York →

Jurisdictional Context

Why local counsel matters in New York

Practicing law in New York. Legal matters in New York are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in New York are typically filed in the local municipal court or the appropriate New York state district court, depending on subject matter and amount in controversy. An attorney licensed in New York brings working knowledge of local procedural deadlines, judicial practices in this andnue, and the substantive law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in New York courts without local counsel or pro hac vice admission.

Looking for additional New York attorneys? Browse all attorneys in New York or all attorneys in New York.

Frequently Asked

Common questions about Marion C. Leydier

Where is Marion C. Leydier's law office located?
Marion C. Leydier's law practice is located in New York, New York. The firm is Sullivan And Cromwell Llp. You can contact the office directly through this profile page.
What practice areas does Marion C. Leydier handle?
Marion C. Leydier focuses on business, m&a, securities, consumer, insurance. Each practice area listed reflects experience handling cases of that type in New York.
How long has Marion C. Leydier practiced law?
Marion C. Leydier has 24+ years of legal experience and has been licensed since 2002.
Where did Marion C. Leydier go to law school?
Marion C. Leydier earned their education at (J.D., 2001); (M.B.A. Université, 1997).
How can I contact Marion C. Leydier for a consultation?
You can contact Marion C. Leydier directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.

Education

J.D.
Columbia Law School
- 2001
M.B.A. Université
E.S.S.E.C., Paris
- 1997

Bar Admissions

New York
Admitted: 2002

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