Strategic clarity.
Trusted insight.
Meaningful impact.
Siderofsky Strategic Advisors LLC helps innovative businesses and ambitious leadership teams accelerate growth, navigate complexity and build lasting relationships and long term value.
Meet Stephen Siderow
Founder & Managing Principal
With over three decades of global leadership experience spanning law, corporate strategy and finance, Stephen blends deep sector insights, hands-on execution experience and strong global relationships to help scale growing businesses in financial services, alternative asset management and technology.
Stephen co-founded and grew BlueMountain Capital Management, into a $23 billion AUM multi-strategy alternative asset manager.
As president, he lead business and product development, strategy and all facets of management company operations.
He later served as a Senior Strategist at Millennium Management and earlier, as a senior consultant at McKinsey & Company and lawyer at Cleary Gottlieb.
Stephen currently advises and invests in a select portfolio of forward-looking businesses, including Allposit, NewVest, among others. He also serves on several nonprofit boards, including Itrek, Ars Nova Theater and the Hertzberg Institute for Palliative Care at Mt Sinai Health System reflecting his personal commitment to leadership, education, and service.
Industry focus & experience
Alternative
Asset Management
Wealth Management /
Multi-Family Offices
Financial Technology
Tech-driven
consumer businesses
Professional Services
(Law, PR, Branding)
Functional expertise
We support founders, senior executives, and boards with guidance across
Business strategy & growth planning
Deal structuring (JV/M&A)
Capital formation & investor engagement
Investment product design & launch
Client & stakeholder communications
Organizational design & governance
Talent acquisition, development
& coaching
Selection & pricing of key service providers (legal, accounting, capital placement, PR, etc.)
How we work with clients
We serve as strategic advisors, board members, and direct investors in client ventures.
We align directly with client outcomes, preferring equity-based compensation.
We choose partners with whom we can build enduring relationships and whose businesses often complement each other and never compete.
Why our clients trust us
AllPosit
Michael Liberman
Founder and CEO
“Stephen brings his expertise, experience, and extensive network of contacts in investment management to the Allposit Advisory Board. In short order, he has contributed greatly to our efforts by connecting us with new clients, two new senior hires, several new partnership/JV opportunities, as well as, providing valuable guidance on key strategic decisionsˮ
NewVest
Edward Talmor-Gera
Founder and CEO
“We are thrilled to welcome Stephen as both an Advisory Council member and Strategic Investor in our platform. His deep expertise in alternatives and strategic growth will be invaluable as we continue scaling our index-based approach to private markets.ˮ
Crayhill Capital Management
Josh Eaton
Managing Partner
“Stephen contributed significantly to the growth of our business with insights into product design and strategy, connections to sources of capital and ability to identify, evaluate and hire top industry talent”.
Tallwoods Partners
Michael Resnick
Co-founder and Managing Director
“Stephen has been a trusted friend and partner for many years. He brings a wealth of experience in, and insight into, the financial services industry and has been an invaluable resource as Tallwoods continues to expand its differentiated and highly customized client-focused offerings.ˮ
Crayhill Capital Management
Carlos Mendez
Co-founder
“Stephen can scale businesses while making a mean dirty martini! Dapper, eloquent and worldly, make him an “old-school” (not old) deal making machine gun.”
