John Conlon is a co-leader of Mayer Brown's Commercial Litigation practice. John's litigation and arbitration practice is particularly wide-ranging.  He has significant experience in disputes that involve bankruptcy, judgment enforcement, commodities, banking, securities, hotels, construction, real estate, employment, contracts, and intellectual property claims.  John has frequently represented clients in state and federal courts across the country as well as in international and domestic arbitrations.  He also counsels clients on drafting and structuring transactions to reduce litigation exposure. John recently completed a two week trial in the District of Las Vegas, obtaining a $60 million judgment in his client's favor on piercing the corporate veil and fraudulent conveyance claims. Areas of specialty include:

Securities Litigation and Investigation – Advising corporations, underwriters, accounting firms, corporate officers and directors in securities class actions, derivative actions, arbitrations and SEC investigations.  John led the defense of a series of high profile RMBS litigations on behalf of HSBC. Clients include HSBC, the Trustees of Oppenheimer Mutual Funds, Canadian Imperial Bank of Commerce, Twin Labs and Grant Thornton.

Banking, Private Equity and Financial Institution Litigation – Representing banks, private equity investors and financial institutions in litigations and arbitrations involving claims for breach of contract, lender liability, letter of credit disputes, collateral debt obligations, residential mortgage backed securities, derivatives, commodities futures trading, unauthorized trading and SWAP agreements.  Clients include DZ Bank, Lehman Brothers, Chase Manhattan Bank, Morgan Stanley, Invesco, Fortis, ABN AMRO, Bank of Nova Scotia, the Jordan Companies and Nomura Capital.

Real Estate and Construction - Representing property owners and contractors and governments in disputes over property rights, construction contracts, sales agreements and tax abatements. Clients include Starwood Capital, Morgan Stanley, Lincoln West Partners. W.S. Atkins, the Panama Canal Authority and the Government of Pakistan.

Bankruptcy – Representing creditors and debtors in adversary proceedings and plan confirmation hearings, representing trustees in the investigation and prosecution of claims. Clients include the Joint Administers of Maxwell Communications Corporation, Bank of Montreal, Fleet Capital, Nomura Capital, Bank of Nova Scotia, Generale Bank, CIBC and Bucyrus Erie.

Intellectual Property, Technology, Licensing and Non-Compete Agreements – Representing clients in disputes over use of intellectual property and technology, including claims for breach of contract, copyright and trademark infringement, confidentiality agreements and non-compete agreements.  Clients include Sensus, Ziff Davis Media, New York Stock Exchange, Panera Bread, Brand Industries and Terrapinn Financial Training.

Hotel Litigation – Representing hotel owners and management companies in disputes over management agreements, franchise agreements, property leases and service contracts.  Clients include Starwood Hotels & Resorts Worldwide, Westin Hotels and Al Anwa USA.

John joined Mayer Brown in 1996. Previously, he was associated with another prominent firm in New York. Earlier, he served as law clerk to the Honorable Kevin T. Duffy of the US District Court for the Southern District of New York. In addition to his trial skills, John is proficient in German.

Spoken Languages

  • English
  • German


  • Tethyan Copper Co. v. Islamic Republic of Pakistan – represent Pakistan in defending against enforcement of a $6 billion ICSID award.
  • GUPSCA v. Panama Canal Authority - represent the Panama Canal Authority in connection with a series of disputes over expansion of the Panama Canal.
  • FHFA v. HSBC – represent HSBC in the multi-billion RMBS litigation.
  • Sparta v. DZ Bank – verdict in favor of DZ Bank following three week trial on claims arising out of decision not to renew credit facility.
  • Adelphia Recovery Trust v. Bank of America, et al. – represent Bank of Montreal and its affiliated investment bank in multi-billion dollar fraud and avoidance claims.
  • Morgan Stanley v. Hans Jecklin, et al. – $60 million judgement in favor of Morgan Stanley and Invesco on veil-piercing action and fraudulent conveyance claims against resort developer following two week trial. 
  • F&R v. Fleet Capital Corporation – verdict in favor of Fleet on lender liability and breach of contract claims after one month bench trial.
  • Pacific Metering v. Sensus – arbitration award in favor of Sensus following  one week AAA arbitration on breach of contract claims.
  • Heritage-Crystal Clean v. Dedalo – obtained an award in favor of client on purchase price adjustment claims in ICC arbitration.
  • Real Nutriceutical – obtained a favorable settlement for client in connection with libel suit against a short seller.
  • Intelnet International v. ITT Corporation and Starwood Hotels & Resorts Worldwide – verdict in favor of defendants after three month bench trial on $1.5 billion breach of contract action for provision of telecommunication and media services to hotels.
  • Codelco v. Lehman Brothers – represented Lehman Brothers in an arbitration under AAA’s International rules in connection with claimed unauthorized trading of copper futures.
  • In re Maxwell Communications Corporation (Aboff v. Macmillan) – verdict in favor of Macmillan following two week bench trial on breach of contract claim.
  • IPC Corporation v. Metalsa S.A. de C.V. – ruling in favor of plaintiff on personal jurisdiction following one week bench trial facilitated global settlement of contract and tort claims.
  • Oppenheimer Funds Fee Litigation – obtained dismissal in favor of the trustees of the Oppenheimer Funds in funds fee litigation.
  • Samsung v. Banco Weise – obtained summary judgment on behalf of Banco Weise dismissing all claims arising out of privatization of Peruvian steel company, dismissal affirmed following oral argument to First Department.


Fordham University School of Law, JD
Dean's List
Fordham Law Review

Williams College, BA


  • New York


  • US Supreme Court
  • US Court of Appeals for the Third Circuit
  • US District Court for the Eastern District of Wisconsin
  • US District Court for the Eastern District of New York
  • US District Court for the Southern District of New York