Jonathan Siegfried's practice involves commercial litigation and arbitration with an emphasis in corporate law and cross-border disputes.

Jonathan has represented numerous US and non-US companies in federal and state courts in domestic and cross-border litigations as well as arbitrations under the rules of the International Chamber of Commerce, UNCITRAL, the American Arbitration Association and ICS1D. These matters have involved contract disputes, enforcement of letters of credit, asset recovery, international bankruptcy, accounting and valuation disputes, securities transactions, trademark and copyright disputes, oil and gas litigation and arbitration, real estate transactions and claims under 28 U.S.C. §1782.

Jonathan also serves as a neutral on the Commercial and Large Complex Case Panels of the American Arbitration Association and the International Institute for Conflict Prevention and Resolution (CPR), and as a party-appointed arbitrator in ICC, ICDR, CPR and ad hoc arbitrations.

ATA and ATS actions

Jonathan has been in the forefront of representing financial institutions in defense of claims brought against them under the Ant-Terrorism Act ( "ATA") and the Justice Against State Sponsors of Terrorism Act ("JASTA"), as well as the Alien Tort Statute ("ATS"). He has successfully argued for the dismissal of these lawsuits at the stage of the initial pleading on grounds of standing, jurisdiction and failure to state a claim, and has argued numerous appeals sustaining those dismissals at the appellate level.

Securities actions

Jonathan has represented corporations and investment banks with respect to actions arising under the Securities Act of 1933, the Exchange Act of 1934 and the Investment Act of 1940. He has handled 10b-5 class actions, cases involving public offerings and private placements, offshore funds, insider trading and derivative suits.

General commercial, intellectual property and banking law

Jonathan has advised both domestic and international companies (public and private) on issues relating to officer and directors' liability, corporate governance, contract and commercial disputes involving breach of contract and fraud, derivative actions, accounting and valuation disputes, intellectual property rights, claims arising under unfair competition laws and restrictive covenants, internal investigations, lender liability claims and bankruptcy-related matters.

Energy Litigation

Jonathan has represented companies in the U.S., Africa, Russia, and Latin America relating to disputes arising out of Power Purchase Agreements, transmission lines, supply contracts and joint venture disputes in the oil, gas and coal industries. 

Telecommunications litigation and arbitration

Jonathan represents a number of domestic and international telecommunications companies in complex litigation, arbitration and dispute resolution, including disputes arising out of M&A transactions, restructurings, outsourcings, breach of contract and joint ventures. He has also represented lenders to telecommunication companies in connection with refinancings, loan defaults and workouts.

Real estate litigation and arbitration

Jonathan has represented a number of national and international companies, including developers, contractors and architectural firms, in disputes arising out of real estate developments, foreclosures and joint venture agreements.


Jonathan has served as both an arbitrator and a counsel in numerous domestic and international arbitrations in the following representative areas:


Disputes arising between developers and Governments with respect to claims arising out of Power Purchase and Consortium Agreements, including the construction, development and operation of power plants, shareholder and joint venture disputes, and related Bilateral Investment Treaty disputes.

Intellectual Property:

Disputes arising out of licensing agreements, trademarks, covenants not to compete and trade secrets in the bottling, hotel, investment banking, telecommunications and entertainment industries.


Cross-border arbitrations involving purchase and sale of Korean Life Insurance Company, as well as insurance and reinsurance arbitrations.

Commercial Contracts:

Disputes between foreign investors and/or foreign investors and governments involving joint venture agreements, asset purchase agreements, shareholder agreements, consortium agreements, and commercial contracts, including investor treaty claims by potential cell phone licensees against Eastern European country with respect to discriminatory bidding practices, claim by hotel developers against the Ukraine, claim against the Dominican Republic in connection with potential expropriation of a power plant, BIT claim against African country for unequal treatment.