Real Estate Mediation Center

Jeremy L. Sine

Jeremy Sine

Jeremy L. Sine 

CoSine Real Estate, Inc.10606 Camino Ruiz, Ste. 8-408
San Diego, CA 92126
Phone/Text (619) 930-9020  
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Jeremy L. Sine is a licensed California real estate Broker and the President of CoSine Real Estate, Inc. Mr. Sine’s diverse background includes property management, residential & commercial sales, investments, and real estate mediation/arbitration.Mr. Sine is a tenacious mediator and an ardent supporter of dispute resolution.  Receiving his Mediator Training from the National Conflict Resolution Center (NCRC) in 2000, Mr. Sine has been a mediator for the past 22 years.  Over that time Mr. Sine has presided over hundreds of mediations, with a focus on business and real estate matters.  Mr. Sine graduated from SDSU in 2000 with a degree in Dispute Resolution, with emphasis on Conflict & Conflict Resolution.Mr. Sine, at the helm of his own management company, has over 16 years of asset and property management experience and is responsible for the oversight of approximately 400 managed rental units comprised of condos, single family homes, multi-family, mixed-use and commercial properties. For both private and institutional investors, Mr. Sine has managed a variety of product types, including multi-family, office, industrial/warehouse properties, retail and single family.  This varied background of accomplished dispute resolution coupled with real world hands-on leadership and management gives Mr. Sine a unique and extremely applicable set of skills as a mediator. 


  • Small Claims Court Mediation – Mediated hundreds of onsite small claims cases covering business, real estate, landlord tenant and other small claims matters.
  • Community Mediation – Mediated hundreds of community mediations covering neighbor disputes (we call them tree & dog disputes), small business matters, real estate matters, HOAs and restraining orders.
  • Large-group Complex Mediation Panel – Mediated disputes and facilitated discussions between large groups on complex matters.
  • Mediator Credital Trainer/Evaluator – A Trainer and Evaluator for NCRC’s Mediation Credential Program.
  • Family Court Mediation Program – Mediated cases referred directly by the Judges in Family Court to resolve disputes and facilitate discussions outside the jurisdiction of the Court.
  • Hearing Officer for the City & County of San Diego – Presiding Officer, on hundreds of Hearings, who issued final rulings on Section 8 program violations for the City & County of San Diego. 


Broker / Owner for CoSine Real Estate, Inc., 2006 – current

Mr. Sine oversees approximately 400 rental units comprised of residential, multi-family, mixed use and commercial assets providing Mr. Sine with an extensive background and understanding of the day to day requirements of property management as well as a firm understanding of obligations by managers, owners and tenants.

Broker of Record for NextHome Citrus City, 2017-2020

Oversaw a residential real estate office of 12 agents.

Broker / Owner for NextHome Advantage, 2015-2020

Started a new NextHome residential real estate franchise office with over 20 million in sales.


National Conflict Resolution Center (NCRC)

  • Community Mediator specializing in real estate, small claims & business disputes
  • Trainer / Evaluator for the Mediator Credential Program
  • Large Group & Complex Mediation Panel
  • Family Court Mediation Program Panel
  • Hearing Officer / Arbitrator

Greater San Diego Association of Realtors

  • Board of Directors, 2018-current
  • BOD Executive Committee, 2020-current
  • Treasurer, 2022-2023

California Association of Realtors

  • Director, 2019-current

Good Shepherd Catholic School

  • Parent-Teacher Board, Treasurer, 2021-2022


  • Licensed CA real estate Broker (DRE# 01719100), 2006-current
  • Certified Negotiation Expert
  • Mediator Credential, NCRC


  • San Diego State University, B.A. in Dispute Resolution with emphasis on Conflict & Conflict Resolution, 2000