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Ian Sigalow

Co-Founder and Managing Partner at Greycroft

Ian Sigalow is a prominent venture capitalist and entrepreneur with extensive experience in the technology and investment sectors. Here are some key details about Ian Sigalow:

Professional Background

  • Co-Founder and Managing Partner at Greycroft, a seed-to-growth venture capital firm headquartered in New York and Los Angeles12
  • Founded Greycroft in 2006 and has since led numerous successful investments1

Board Positions

Ian Sigalow holds board positions at several companies, including:

  • Alium (Board Member)
  • Fetch (Board Member)
  • Pie Insurance (Board Member)
  • HealthVerity (Board Member)
  • Branch (Board Member)
  • Hidden Road (Board Member)
  • Landing (Board Member)
  • Stable (Board Member)
  • ClosedLoop.ai (Board Member)
  • Ergatta (Board Member)
  • Amplify Life Insurance (Board Member)
  • TOGGLE AI (Board Member)2

Previous Experience

  • CEO/Founder of StrongData Corporation (2004-2006)
  • Associate at Boston Millennia Partners (2001-2004)2

Education

  • BS in Economics from Massachusetts Institute of Technology (1997-2001)
  • MBA from Columbia Business School (2004-2006)2

Ian Sigalow's LinkedIn username is indeed iansigalow.2

Highlights

Oct 14 · twitter

Market operators care about what happens next.

What if the Fed cuts rates, but oil spikes because of a shipping crisis in the Strait of Hormuz? What if guidance misses while commodities rally? What if AI spending accelerates, but doesn’t translate into margin?

Answering those questions used to take days. Analysts would scan filings, track macro indicators, review earnings transcripts, and write a memo by hand. By the time the research was ready, the market had already moved.

Reflexivity does that work in minutes.

In 2020, Jan Szilagyi walked into my office with a whiteboard and a thesis: research would not scale through automation alone. He was already building a copilot that could interpret filings, earnings, and global signals, then reason through them the way an analyst would.

He and his co-founder Giuseppe Sette had both served as CIOs at hedge funds. Their job was to understand how complex, dynamic events flowed into asset prices. There was no platform for that kind of reasoning. So they built internal tools with Kensho-trained engineers that used hand-coded queries, stitched-together dashboards, and fragmented data pipelines.

That stack became the foundation for Reflexivity.

The earliest version focused on modeling “what if” scenarios, the kind of analysis Jan and Giuseppe used to run manually. They had the technical depth to move from summaries to simulations, and the conviction to build a system around it.

When GPT changed how people interfaced with software, the team rebuilt from first principles. They designed a proprietary knowledge graph for financial markets – a self-learning repository that is constantly mapping the financial landscape. They enabled tool-calling across filings, earnings, and macro signals. They trained the system to return full analysis, including charts, narratives, and logic chains grounded in real inputs.

Today, Reflexivity is deployed inside Interactive Brokers and expanding across some of the world’s largest hedge funds, asset managers, and wealth advisors. It is the first MCP client in financial services, making it a multi-modal command platform that can retrieve, reason, and eventually act.

What began as a whiteboard sketch in 2020 is now used by hundreds of investors - from hedge funds to family offices - who rely on Reflexivity to do in minutes what once took weeks. It’s become part of the research rhythm inside some of the world’s most sophisticated firms.

We are proud to partner with Jan, Giuseppe, and the Reflexivity team to help build the future of institutional research infrastructure.

Market operators care about what happens next.

What if the Fed cuts rates, but oil spikes because o
Aug 18 · twitter

I love this idea of measuring “wealth creation for other people.” Part of the reason that I like being the first investor in companies, particularly ones that are not consensus ideas at the time, is that I can help will these things into existence. And in doing so we create wealth for so many people.

Jun 6 · TechCrunch
Greycroft co-founder Ian Sigalow on investing $1B in this market - TechCrunch
Greycroft co-founder Ian Sigalow on investing $1B in this market - TechCrunch
May 12 · Business Insider
Greycroft's Ian Sigalow predicts more acquisitions for Uber - Business Insider

Related Questions

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Ian Sigalow
Ian Sigalow, photo 1
Ian Sigalow, photo 2
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Experience

Co-Founder and Managing Partner at Greycroft
Founder at StrongData Corporation, Associate at Boston Millennia Partners

Education

BS in Economics from Massachusetts Institute of Technology, MBA from Columbia Business School

Location

New York, New York, United States