About the Firm

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Our Practice

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Our Attorneys

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About the Firm

The firm was founded in 2003 and has offices in the financial district of downtown San Diego. Its shareholder, Audie de Castro, previously worked for a larger corporate law firm. He founded his own firm so that he could offer much more personalized services at reasonable rates. We have a business approach to practicing law. We learn our clients’ businesses and listen to their needs. Our focus on the specific needs of clients helps us achieve legal and business success for them cost-effectively. That is why we have been retained to represent private and publicly traded companies, domestic and international. We have represented clients in the United States and other countries, including Canada, China, Germany, the Philippines and the UK. Audie de Castro is the Philippine Honorary Consul of San Diego.

We have represented domestic and international clients on a regular basis over many years. We advise them on day-to-day business matters as corporate counsel. We have successfully negotiated and closed complex, multi-million dollar deals. Some of our key business practice areas include corporate governance, limited liability company laws, securities offerings and compliance, mergers & acquisitions, commercial real estate, licensing and distributorships, and business agreements.

Our clients trust us to represent them when they are involved in major disputes, no matter the opponent. We have successfully handled contentious and high stakes litigation in state and federal courts, including cases involving breach of contract, breach of fiduciary duty, shareholder and partnership disputes and arbitration, fraud, securities, franchise, real estate, and other commercial disputes. We advise our clients to be practical about resolving disputes. But we will vigorously litigate disputes when it makes business sense to do so, including going to trial.

Our Practice

We are a full-service business and civil law firm. We successfully handle both transactional and litigation matters for businesses, entrepreneurs, investors, and individuals.
We practice in the following areas:


  • Breach of Contract
  • Fraud
  • Breach of Fiduciary Duty
  • Corporate Governance
  • Shareholder and Partnership Disputes
  • Franchise Disputes
  • Real Estate Disputes
  • Securities
  • Employment
  • Negligence


  • Contract Review
  • Entity Structuring and Formation,
    including Corporations, LLCs and LPs.
  • Corporate Governance
  • Securities Offerings, Public and Private
  • Securities compliance
  • Rule 144 transactions
  • Mergers & Acquisitions
  • Commercial Loan Financing
  • Commercial Real Estate Acquisition and Leasing
  • Licensing and Distributorships

Our Team

Audie J. de Castro

Audie de Castro practices in business litigation and transactional law. He has extensive experience in litigating business, corporate, employment, real estate and investment matters, including fraud or misrepresentation, breach of fiduciary duty, securities, franchise disputes, accounting, and breach of contract claims. He has obtained large settlements and has won trials. He was featured as a Super Lawyer (Business Litigation) by Super Lawyer Magazine in 2021, 2022, and 2023.

He has closed complex and large transactions, such as mergers and acquisitions, securities offerings, franchising, licensing, distributorships, and commercial real estate deals. He has represented public and private companies.

Mr. de Castro graduated cum laude from the University of San Francisco School of Law. He was a senior staff member of the University of San Francisco Law Review and McAuliffe Honor Society (top 10%). He is admitted to practice in all California state courts, the U.S. District Courts in the Northern, Southern and Central Districts, and the 9th Circuit Court of Appeals. He received a business degree from the University of San Diego and obtained a CPA license (inactive).

He is a member of the San Diego County Bar Association, the American Bar Association and the American Health Lawyers Association. Mr. de Castro has taught Business Associations as an Adjunct Professor of Law at Thomas Jefferson School of Law.

Since 2014, Mr. de Castro has served as the official government representative of the Republic of the Philippines, for San Diego County. He is the country’s Honorary Consul and overseas a jurisdiction of over 200,000 constituents.

Mr. de Castro is prominently involved in civic affairs. He previously served on the Board of Governors for the San Diego Foundation. He is also past President of the Asian Business Association of San Diego and the Filipino-American Lawyers of San Diego. He is a graduate of LEAD San Diego (2003).

He enjoys spending time with his wife and two boys, exercising, and cooking.  He speaks Tagalog and English. 


Jonathan J. Elia

Jonathan practices business litigation and represents both individuals and businesses in their various legal needs. He began his legal career in one of California’s largest workers’ compensation defense firms. He then joined a plaintiff’s personal injury firm, before making his way to business litigation. Jonathan’s varied legal experience allows him to assist clients with their legal needs beyond business litigation.

Jonathan received his B.A. in Criminal Justice from San Diego State University in 2015 and received his Juris Doctorate from the University of San Diego in 2018 with a concentration on business and corporate law. He passed the bar in 2018, is admitted to practice in all California state courts, the U.S. Southern District Court, and is a member of the San Diego County Bar Association. He also speaks Romanian.

He spends his free time, traveling, trying new foods, and watching e-sports with friends


John R. Mayer, Of Counsel

John represents businesses and individuals in their various legal needs, including litigation, corporate and transactional work, real estate matters, employment-related issues, and class action defense. Having worked as general counsel for two companies, John brings a business world practicality to his practice of law.

John received his B.A. from the University of California, Santa Barbara in 1994 and graduated cum laude from Thomas Jefferson School of Law in 1998, where he was a member of the Thomas Jefferson Law Review. After passing the California bar exam, he practiced with the mid-sized law firm Hayes Simpson Greene LLP until late 2001, when he started his own practice. Since then, he has practiced with a partner and as a solo practitioner, and he established John R. Mayer, A Professional Law Corporation in 2005.

John has been active in the community for many years, having served as president and a board member of San Diego Teen Court, a non-profit peer sentencing program for first-time juvenile offenders, and on the board of directors for Outdoor Education Foundation, a non-profit fundraiser for Sixth Grade Camp at Cuyamaca. John is also a licensed California real estate broker.

John is married, to wife Vanessa, and they have two young boys (Jordan and Nash).

Kateryna Borge

Ms. Borge is a multilingual translator and interpreter. Fluent in four languages, she speaks Russian, Ukrainian, English and French. She graduated from Kyiv National Linguistic University and received a certification from the University of Geneva and a private French school in Nice, France. She is a member of American Translators Association and Association of Translators & Interpreters in the San Diego area. Participated in Model United Nations and European Youth Parliament sessions.

Ms. Borge has a background in law, business and finance and is the firm’s paralegal. Prior to joining the firm, Ms. Borge held a legal internship in the San Diego Superior Court and worked in a personal injury law firm. She is a member of the San Diego Paralegal Association. Ms. Borge is a volunteer translator and interpreter for a local non-profit law center that provides services to victims of human and civil rights violations and is a Special Recognition Awardee of the 2022 La Mancha Awards. With her strong international background, she also handles consular matters for the Philippine Consulate, San Diego.

In her free time, Ms. Borge enjoys reading, hiking and photography.


Camille Balatbat

Ms. Balatbat is a well-rounded youth mentor and project manager. She speaks Tagalog, Pangalatok, English, and Spanish. She also graduated summa cum laude from San Diego State University (SDSU) with a B.A. in Psychology and a Minor in Counseling and Social Change (CSC) in 2021. While pursuing her education, she advised underrepresented students as one of the peer mentors of Southwestern College Alpha Omega Campus Club and of SDSU Andres Bonifacio (AB) Samahan Student Outreach and Academic Resources (SOAR) Board. She also directed multiple projects such as SDSU CSC Graduation Ceremony in three months and San Diego Church of Christ (SDCC) 2021 Summer Teen Camp in two months. Camille held clerical positions like Student Employment Services Front Desk Clerk, Extended Opportunity Programs and Services (EOPS) Receptionist, and SDCC Administrator prior to joining the firm.

With her exceptional work ethic and passion to help people, she serves as the firm’s administrative assistant and manages consular matters for the Philippine Consulate of San Diego.

In her spare time, she loves crafting, getting boba with friends, and spending time with her husband.


Contact Information

We are centrally located within the financial district of downtown San Diego. We are on the 17th floor of the Bank of America Building. Our offices are within walking distance of Federal and State courthouses. Our contact information is below: 701 B Street, Suite 1745
San Diego, California 92101
Phone: (619) 702-8690
Facsimile:(619) 702-9401

If you wish to contact us, please email us at adecastro@decastropc.com and we will respond to you shortly. If this is an urgent matter, please call us directly at (619) 702-8690.