SeaRock Ventures was founded on the belief that enduring economic value is created through direct operational involvement and long-term strategic patience. Rather than acting as a passive financial allocator or a single-industry developer, SeaRock functions as an active holding platform.
We deploy capital into operating businesses, real assets, and strategic special situations where hands-on management, financial clarity, and execution discipline can generate compounding value.
Operating Philosophy
Long-Term Perspective
We are unconstrained by artificial fund expiration deadlines, allowing us to make decisions that maximize long-term asset value and resilience.
Disciplined Execution
Great strategy creates value only when matched with meticulous field oversight, budget control, and milestone accountability.
Hands-On Operating Experience
Our principals bring real-world experience running companies, managing construction jobsites, and navigating complex balance sheets.
Trusted Relationships
Decades of collaborative partnerships with lending institutions, municipal bodies, and business owners form the core of our platform.
Platform Leadership
Our leadership brings direct operational involvement, disciplined capital stewardship, and decades of hands-on experience in finance, development, and enterprise growth.
Thayer Flynn
Founder & Managing Principal / CEOThayer Flynn is a highly skilled infill real estate developer and investor with a diverse background in finance, accounting, and construction. Born into a family of builders and developers in San Diego, Thayer has been deeply involved in the world of real estate from an early age. His extensive experience and industry knowledge have made him a go-to leader for unique, innovative urban infill housing projects throughout Southern California.
Thayer holds a Bachelor’s degree in Finance from the University of Southern California (USC), which, combined with his background in construction and accounting, has given him the unique ability to manage the financial and physical aspects of real estate projects with precision. He is a licensed broker by the CA Department of Real Estate (Lic. # 01760575), and his career is marked by award-winning multifamily development projects and value-add investments.
As a member and co-chair of the ULI San Diego Small Scale Infill Developer group, Thayer is passionate about creating sustainable and livable communities through infill development. Whether working on ground-up construction or complex value-add renovation, Thayer’s goal is always to deliver projects that enhance quality of life for residents and generate enduring value for the community.
Megan Flynn
Chief Financial Officer (CFO)Megan Flynn is a highly accomplished executive with extensive experience in financial management, business process optimization, and capital project management. With over 15 years of leadership experience, she has established herself as a seasoned leader and an expert in fiscal strategy and operational governance.
Throughout her career, Megan has held senior positions across multiple organizations, where she has demonstrated her ability to lead cross-functional teams and drive measurable results. She has a proven track record of improving financial performance and operational efficiencies through robust reporting, internal controls, and execution discipline.
Megan’s expertise in project management enables SeaRock to successfully manage complex initiatives and deliver projects on schedule and within budget. Her ability to manage stakeholder relationships and align organizational resources has been instrumental in platform growth.
Lee Mills
Vice President, MarketingLee Mills is an accomplished marketing and advertising executive with more than two decades of senior industry experience. Renowned for strategic vision and tactical execution, Lee directs brand equity, investor marketing, and communications across the SeaRock platform and its holding businesses.
Lee began his career in marketing and advertising after serving in the United States Navy. He quickly rose through the ranks, gaining comprehensive experience across account management, creative direction, brand positioning, and media planning.
Lee is known for his exceptional leadership skills and his ability to inspire and mobilize teams to achieve their highest potential. He has a keen eye for talent and has built and directed successful creative and marketing teams throughout his career.
The SeaRock Legacy: Three Generations of Building
Thayer Flynn is a local San Diegan and father of two daughters. Thayer’s San Diego roots run deep, and his builder, developer, and real estate investor heritage is just as strong—spanning three generations and over six decades of actively building and revitalizing the region’s urban fabric.
John Mortenson — Pioneer Custom Home Builder
Thayer’s grandfather, John Mortenson, was a builder and developer who became renowned throughout the local housing industry as an innovative designer and builder of custom homes. Over a period of twenty years, John designed and constructed more than 200 custom-built houses in the San Diego area, establishing a family tradition of architectural excellence, structural integrity, and enduring craft.
Gregg Flynn — High-End Residential Builder & Developer
Thayer’s father, Gregg Flynn, is a high-end residential builder and developer who spent the majority of his distinguished career in San Diego crafting premier custom residences before retiring to Albuquerque, New Mexico. Gregg instilled the core values of uncompromising jobsite oversight, budget discipline, and hands-on craftsmanship that define SeaRock today.
Chris Mortenson — Gaslamp Revitalization & The "Baby Del"
Thayer’s uncle, Chris Mortenson, also a builder and developer, was among the first visionaries to see the revitalization potential of downtown San Diego’s historic Gaslamp Quarter. Known for his pioneering historical renovations, Chris developed hundreds of condominiums and apartments and more than half a million square feet of industrial, office, and commercial space across San Diego.
Among his most legendary achievements, Chris Mortenson is celebrated for the historic preservation and relocation of the famous “Baby Del” Queen Anne Victorian residence to Coronado in 1985. The monumental project required the historic mansion to be barged across San Diego Bay with authorization from the United States Navy—a feat that remains an indelible milestone in San Diego architectural and maritime history.
Continuing the Tradition Through SeaRock Development
Today, SeaRock Ventures carries forward this multi-generational legacy through disciplined urban infill development, value-add acquisitions, and strategic capital allocation across Southern California.
Explore the Development Portfolio →