Atty. David C. Mahaffey

Atty. David C. Mahaffey

David is the managing partner of the Washington, D.C. office, as well as the co-leader of the Investment Management Group. Prior to joining Sullivan & Worcester, David was Special Counsel in the Washington, D.C. office of Gibson, Dunn & Crutcher.

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Profile Summary

About David C. Mahaffey at a glance

David C. Mahaffey is a securities attorney based in Washington, District of Columbia, practicing at Sullivan & Worcester LLP. Admitted to practice in District of Columbia, The District of Columbia Bar. Educated at Harvard University (J.D., 1982) and Princeton University (B.A., 1979). Recognitions include Best Lawyers in America — Mutual Funds Law (2026), Best Lawyers in America — Securities Regulation (2026), and Best Lawyers in America — Additional Areas of Practice: (2026). Serands clients in Washington, DC and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

  • David is the managing partner of the Washington, D.C. office, as well as the co-leader of the Investment Management Group
  • Prior to joining Sullivan & Worcester, David was Special Counsel in the Washington, D.C. office of Gibson, Dunn & Crutcher
  • He previously served as Assistant General Counsel for Legislation and Investment Company and Adviser Regulation at the Securities and Exchange Commission and as Counsel to SEC Commissioner Aulana Peters

Practice Areas Explained

David C. Mahaffey's Areas of Practice

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

Securities Law

David C. Mahaffey is one of 64,529 securities attorneys indexed nationally. Browse securities attorneys in District of Columbia →

Jurisdictional Context

Why local counsel matters in District of Columbia

Practicing law in District of Columbia. Legal matters in District of Columbia are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantive law. Cases originating in Washington are typically filed in the local municipal court or the appropriate District of Columbia state district court, depending on subject matter and amount in controversy. An attorney licensed in District of Columbia 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 District of Columbia courts without local counsel or pro hac vice admission.

Looking for additional District of Columbia attorneys? Browse all attorneys in Washington or all attorneys in District of Columbia.

Frequently Asked

Common questions about David C. Mahaffey

Where is David C. Mahaffey's law office located?
David C. Mahaffey's law practice is located in Washington, District of Columbia. The firm is Sullivan & Worcester LLP. You can contact the office directly through this profile page.
What practice areas does David C. Mahaffey handle?
David C. Mahaffey focuses on securities. Each practice area listed reflects experience handling cases of that type in District of Columbia.
Where did David C. Mahaffey go to law school?
David C. Mahaffey earned their education at (J.D., 1982); (B.A., 1979).
How can I contact David C. Mahaffey for a consultation?
You can contact David C. Mahaffey 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.
What awards or recognition has David C. Mahaffey received?
David C. Mahaffey's notable recognition includes: Best Lawyers in America — Mutual Funds Law; Best Lawyers in America — Securities Regulation; Best Lawyers in America — Additional Areas of Practice:; Best Lawyers in America — Securities / Capital Markets Law; Best Lawyers in America — Awards:.

Education

J.D.
Harvard University
- 1982
B.A.
Princeton University
- 1979

Awards

Best Lawyers in America — Mutual Funds Law
- 2026
Best Lawyers in America — Securities Regulation
- 2026
Best Lawyers in America — Additional Areas of Practice:
- 2026
Best Lawyers in America — Securities / Capital Markets Law
- 2026
Best Lawyers in America — Awards:
- 2026
Best Lawyers in America — Chambers Global,
- 2026
Best Lawyers in America — Ranked in Investment Funds (2021-2023)
- 2026
Best Lawyers in America — Chambers USA
- 2026
Best Lawyers in America — , Ranked in Investment Funds (Nationwide) (2015-2022)
- 2026
Best Lawyers in America — The Legal 500 U.S.
- 2026
Best Lawyers in America — (2012-2022)
- 2026
Best Lawyers in America — (2009-2023)
- 2026
Best Lawyers in America — Washington, D.C.
- 2026
Best Lawyers in America — Super Lawyers
- 2026
Best Lawyers in America — , Securities/Corporate Finance (2014-2017)
- 2026
Best Lawyers in America — Martindale-Hubbell
- 2026
Best Lawyers in America — featured AV Peer Review Rated
- 2026

Bar Admissions

District of Columbia, The District of Columbia Bar

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