(Bloomberg) -- Proof Trading Inc., an algorithmic-trading platform built by former IEX Group Inc. strategists, hired Nila Das from Citigroup Inc. to join its executive team.

Das, who spent nearly a decade at Citigroup trading mortgages and was previously at RBC Capital Markets, joins the broker-dealer as chief operating officer, according to co-founders Allison Bishop and Daniel Aisen. Das started in September at the New York-based firm, where she is responsible for business development and sales strategy.

Proof Trading also promoted Marcio Moreno, vice president of engineering, to chief technology officer. Moreno joined the firm in July after 11 years at Goldman Sachs Group Inc., where he held various engineering roles in Sao Paulo and New York. He takes over as CTO from Prerak Sanghvi who left earlier this year to join Clear Street. Co-Founder and Chief Software Architect Beau Tateyama decided to step back from Proof in 2021.

“We had a massive loss on the engineering side and we needed to fill that hole to get back to full strength,” Aisen said in an interview.

Founded in 2018, Proof built its broker-dealer platform to disrupt traditional financial markets, which it considers opaque and complicated. The founders come from IEX, the exchange that touts its fairness and transparency. Proof takes a similar approach, with blog posts about its technical development and recent executive turnover. It also publicly releases data reports and performance statistics.

The new hires will help the company refocus on its mission, Bishop said.

“We have a team now that has given up a lot to be here,” she said. “It’s an opportunity to have more impact and play a role in shaping the future of the company.” 

Proof’s trading platform offers buy-side and sell-side clients two algorithms: one that follows a more traditional model known as volume-weighted average price, or VWAP, and another that balances finding a counter-party for a big trade with lessening the potential impact of the trade.

Aisen said the firm trades almost half its executions on IEX’s exchange. Proof’s founders have sold all their equity in IEX and no longer have financial ties to their former company. They favor the exchange because of execution quality, he said.

Proof, which is registered as a broker-dealer with the Financial Industry Regulatory Authority, has re-registered to amend its ownership, with Bishop eventually becoming the majority owner, she and Aisen said. That would make Proof a rare Wall Street broker-dealer platform majority-owned by a woman. 

(Updates with co-founder name in third paragraph. An earlier version corrected the name of the company’s previous CTO.)

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