Sonja Kohn: Hero or Villain? The Untold Story of Wall Street’s “Double-Sided Grandmother”

In the history of the financial world, few figures have lived in two such diametrically opposed parallel universes as Sonja Kohn.

If you were to meet her in the Monsey community of New York—an ultra-Orthodox Jewish enclave—you would see a kindly grandmother. She wears the sheitel (wig) mandated by religious law, dresses in modest skirts, and presides over Shabbat dinners surrounded by dozens of grandchildren.

But if you met her at the Vienna State Opera or on the financial streets of Milan, you would see a formidable queen of finance. She was the founder of Bank Medici, a legend known as “Austria’s Woman on Wall Street,” and the gatekeeper who could once open the door directly to Bernie Madoff’s office.

This is the story of Sonja Kohn: a tale of how the daughter of Holocaust refugees climbed to the top of the pyramid, fell into the abyss of the largest Ponzi scheme in history, and miraculously rebuilt herself from the ruins.

How Did an Orthodox Grandmother Become a Wolf of Wall Street?

The story begins in 1980s New York.

Sonja was born in Vienna to parents who were Jewish refugees from Eastern Europe—Holocaust survivors. This background often imbues descendants with a specific survival instinct: an extreme sensitivity to risk and a fierce hunger for security and wealth.

When she moved to New York with her husband, she didn’t choose to be a traditional housewife. She joined Merrill Lynch, becoming one of the few female stockbrokers of that era. In a Wall Street filled with testosterone and cigar smoke, Sonja discovered she possessed a weapon others lacked: Trust.

She navigated effortlessly between two worlds, a duality that would form the backdrop for her later tragedy and glory:

Was It the Perfect Deal or a Faustian Bargain?

At the time, Madoff was a god on Wall Street. His funds never lost money, but he was incredibly arrogant, often turning away investors’ money. This “exclusivity” made him irresistible to Europe’s wealthy elite.

Sonja Kohn smelled an opportunity. She returned to Vienna and founded Bank Medici. Although the name sounded like an Italian noble bank with centuries of history, in reality, it was a funnel custom-built for Madoff.

Sonja sold a concept to European royalty, politicians, and Russian oligarchs: “I know Madoff. I have the key to the secret garden.”

It was a brilliantly designed symbiotic relationship:

• Madoff needed a constant stream of new capital to sustain his Ponzi scheme.
• Sonja created “feeder funds” (like Thema International) to channel client money to Madoff.
• Madoff claimed he “didn’t charge management fees,” which allowed Sonja to legitimately charge her clients high placement and performance fees.

For a long time, it was the perfect business. Bank Medici’s balance sheet was flawless, and Sonja was viewed as a financial alchemist. That is, until the devastating morning of December 11, 2008.

Where Did She Go When the House of Cards Collapsed?

When Madoff confessed to his sons that “it’s all just one big lie,” Sonja Kohn’s world imploded instantly.

Overnight, she went from a respected banker to Public Enemy Number One.

Irving Picard, the trustee for the Madoff liquidation, slapped her with a lawsuit seeking $19.6 billion. In his complaint, he wrote a sentence that destroyed Sonja’s reputation: “In Sonja Kohn, Madoff found a criminal soulmate.”

Picard alleged she was not a victim but a co-conspirator. He claimed that for decades, through complex means, she had received at least $62 million in secret kickbacks from Madoff.

But for Sonja, the legal accusations weren’t the most terrifying part. The most terrifying part was her client list.

Bank Medici had attracted vast sums of “new money” from the former Soviet Union and Eastern Europe. These clients had lost hundreds of millions of dollars, and they were not the type to settle problems through polite legal letters.

So, the once high-profile banker “vanished.” For the next two years, the media was filled with speculation about her whereabouts. Some said she was in Zurich; others said she was in Tel Aviv. She cut off electronic communications and moved frequently. She was hiding not just from the FBI, but from a potential “kill order” issued by angry capital from the East.

Guilty or Gullible? How Did She Beat the Charges?

Just when everyone thought she would spend the rest of her life in prison, the plot twisted dramatically in 2013.

In a trial at the UK High Court, Sonja Kohn played her ace card. Facing the accusation of being a co-conspirator, her defense logic was simple yet powerful: “If I really knew it was a scam, why would I have invested my own family’s life savings into it?”

Evidence showed that in the final months before the scheme collapsed, Sonja was still frantically pouring her family’s pension funds into Madoff’s hands.

British Judge Andrew Popplewell ultimately accepted this narrative. He ruled: Sonja Kohn was indeed greedy, and she indeed charged exorbitant fees, but in the financial world, greed is not a crime. She was a victim, thoroughly duped by Madoff, not a co-conspirator.

She won the lawsuit, but it was a Pyrrhic victory. Her bank was shuttered, her reputation was in tatters, and the powerful figures who once surrounded her now avoided her like the plague.

Can Artificial Intelligence Offer Redemption from the Ruins?

If the story ended here, it would simply be a tale of survival. But Sonja Kohn was clearly not content with just being a survivor.

In 2015, nearing her 70s, she made a decision that surprised everyone: She started a new company.

This time, she didn’t touch hedge funds or Ponzi schemes. She pivoted into the cutting edge of technology—Artificial Intelligence.

She founded a company called BestFit. In a way, it was a digital summary of her life’s experience. BestFit uses behavioral science and AI to help banks analyze a customer’s personality, thereby recommending the products they are most psychologically likely to buy.

There is a profound, dark humor in this: She was once defeated by Madoff’s psychological tactics, losing everything; now, she is attempting to use AI to decode and quantify those very tactics.

What Is the True Legacy of a Survivor?

Today, in 2025, Sonja Kohn is an octogenarian. Yet, she remains active in fintech forums across Switzerland and Austria, speaking about Generative AI and digital transformation.

When you watch her speak eloquently on stage, it is hard to connect her with the woman who was once hunted by both the FBI and the Russian mob.

Who is she, really? Is she the greedy “feeder” who funneled billions into a furnace? Or is she the ultimate survivor, a woman who carved a bloody path through the male-dominated jungle of global finance, and who, even after total destruction, managed to rise again?

Perhaps, like her double life, the truth lies somewhere in the gray. But one thing is certain: on the ruins of Wall Street, Sonja Kohn didn’t just survive; she learned how to use the rubble to build a new castle.