By Jessica Darmoni
“The (trading) industry is built on people working together,” explains Nancy Stern. “You have to think of your interactions as long-term relationships. Something that makes sense in the short term may not serve you—or others—over time. You always have to ask: what are the unintended consequences?”
That long-term view has shaped Stern’s approach at career inflection points, business strategies and regulatory guidance. After first speaking with Stern over 10 years ago, The Glass Hammer sat down with her to talk about where she is now.
Today, as Managing Director and General Counsel of Simplex Trading, Stern stands at the intersection of market structure, regulation, technology, and leadership. She is the first, and only, lawyer at the 20-year-old market-making firm, a role that requires both precision and perspective.
Building Legal Infrastructure in a High-Speed Market
Simplex Trading operates as a market maker in the fast-moving world of equity options, where milliseconds matter and volumes have exploded. They continuously buy and sell options to capture the bid-ask spread. The firm is connected to 17 exchanges and has traders on the trading floor at Cboe Global Markets.
Over the past decade, the equity options market has transformed dramatically. Retail participation has surged. Trading volumes have exploded. Zero-day-to-expiration (0DTE) options have compressed time horizons to a single day—sometimes blurring the line between investment and entertainment for retail traders. In this environment, risk evolves quickly.
“We are in the business of taking risks,” Stern says. “My job is evaluating those risks. You have to understand the full picture—but most importantly, you have to adapt.”
Simplex historically relied on outside counsel. As the business grew more sophisticated, leadership recognized the need for an in-house legal leader to manage risk proactively, implement processes, and help shape culture from within.
Stern stepped into that role not only to mitigate legal exposure, but to build systems that support sustainable growth.
Her mandate includes implementing new procedures, strengthening governance, and aligning culture with regulatory expectations, all while keeping pace with accelerating technological change, including the integration of AI tools that are reshaping industries at unprecedented speed.
“The pace of change continues to accelerate,” she notes. “The tools are new but in many ways, the challenges are iterations of what we’ve faced before. That’s what makes it exciting to put these new tools into practice.”
From General Counsel to CEO, and Back Again
The Glass Hammer first met Stern in 2015 as Executive Vice President, General Counsel and Secretary of Allston Trading. She went on to become CEO of the proprietary trading firm, which was then acquired by DV Trading in December 2021. After the acquisition she joined futures commission merchant and clearing firm, ABN Amro, as Chief of Staff and General Counsel until 2024.
Her earlier career includes partner roles at Katten Muchin Rosenman LLP and Gardner Carton & Douglas LLP (now Faegre Drinker Biddle & Reath LLP), where she built the legal foundation that would later support her executive leadership.
Transitioning from General Counsel to CEO required more than technical skill, it required self-awareness.
“Coaching was very important to me,” Stern reflects. As she prepared to step into the CEO role, she worked with an executive coach and encouraged her team to do the same. “Understanding your strengths and weaknesses is essential. Sometimes you need someone outside your organization to help you think clearly.”
That investment in self-knowledge became a catalyst for growth.
Resilience, Realism, and Knowing When to Walk Away
Leadership, especially in high-stakes financial environments, inevitably includes moments of doubt. Stern approaches setbacks with a problem-solver’s mindset, and with realism.
“You have to ask yourself: Is this a situation I can improve? Or should I walk away? Can I make this better, or would someone else do a better job?”
She describes herself as loyal and deeply committed however she also recognizes limits. Not every system can be fixed from within and not every environment is the right one.
For women navigating leadership roles, that distinction is powerful: resilience does not mean staying at all costs. It means making thoughtful, courageous decisions about where you can create impact.
Mentorship in All Directions
When asked who influenced her most, Stern doesn’t name a single figure.
“I’ve been fortunate to have mentors at every stage and from all directions,” she says. “Senior people, junior people, peers.”
She learned the craft of law from colleagues in law firms. She learned how to lead organizations by listening to those who understood the pulse of the business and the pain points of its people.
What does she value most?
“Anyone willing to speak the truth, even when it’s difficult.”
Now, she pays that forward. Mentorship is one of the impacts she most hopes to create.
“There are people with tremendous talent who just need guidance on specific questions. If I can help them move forward, that’s incredibly satisfying.”
What the Future Demands from Leaders
As markets evolve, so must leadership. Stern believes future leaders will need empathy and the ability to put others first.
“Strong listening skills, sound judgement and the ability to sift through vast information to make principled decisions will be demanded of our leaders,” she emphasizes.
Stern also believes that execution, the discipline to turn vision into reality will be crucial.
“Vision without execution doesn’t count,” she says.
In an era of accelerating AI adoption, shrinking time horizons, and increasingly complex market participation, those human-centered skills may matter more than ever.
Leading Into the Future
What inspires her now?
“New tools. New experiences. New ways to approach old challenges.”
Despite decades of experience across law firms, trading floors, executive suites, and boardrooms, Stern remains energized by evolution.
Her leadership is not about chasing speed but about thoughtful adaptation, long-term relationships as well as clear-eyed risk assessment and helping others grow along the way.
In industries often defined by volatility, Stern’s career is a reminder that sustainable leadership is built not only on expertise, but on empathy, integrity, and the courage to continually adapt.
