

Castellon Professional Services PC
Certified Public Accountant

Office Visits- Appointment Only 938 E. El Camino Real, Sunnyvale, CA 94087
Locations
"Behind Every Number is Someone Who Cares."

I have had the pleasure to work with Mario in various iterations, projects, and roles over the years. So I can share with complete confidence. He is steadfastly committed to the development of personal excellence when offering advice, service and expert knowledge. Mario is able to see the big picture, effectively keep identify and the relevant details and make recommendations that you can absolutely trust. His credentials are impressive, and more importantly massively helpful as he is like a creative library you get full access to if you get the wonderful chance to work with him.
Trella M. Davis
Mario and his team are super insightful and have been incredible financial advisors and partners for my scaling brand consultancy. They are who you want in your corner when it comes to financial planning, taxes, and strategy.
Beth C.
Mario has been super helpful!
I needed another pair of eyes on my self-prepared return which included some RSU-related complexity and a K1 schedule.
Mario's assistant scheduled a free consultation via Zoom video call for the same day and we went through my return draft together as I was sharing my screen. Mario was friendly and professional, answered all my questions in detail, reassured me about correctness of my returns, and even gave some advice for the future filings.
I will definitely be coming back when I need help with more complex tax situation. Thank you!
Lucas C.
What are our clients saying?
Ratings from the current tax year:
Thank you for your support and quick response to questions. I appreciate your services.
Subodh & Margot, N.
The staff are very prompt and they respond to questions immediately.
Joycelyn P.
I had a great experience getting my taxes prepared this year. The team was patient, friendly, and incredibly thorough. They made the process feel simple and manageable. I appreciated how they walked me through my options and made sure I understood everything before filing.
Rigoberto M.
Its so easy to upload documents.
Henry C.
First class professionals
Andrew C.
I feel very safe working with your company. I had never felt this way before.
Edwiges D.