Asked about the hiring, Modern Markets Initiative spokesman Kevin Madden said, "The MMI members welcome perspectives based on experience when it comes to countering many of the misperceptions folks have about HFT."
In a 2010 speech before the High Frequency Trading World USA conference, Chilton weighed into the debate for the first time: "HFT trading is part of our trading today, but should it remain the same?" he asked. "Is this type of trading outside of—or is it even inimical to—the fundamental purposes of capital formation and risk management in these markets?"
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In a 2011 speech entitled "Caging the Financial Cheetahs," Chilton likened high-frequency traders to the fleet-footed felines of the African prairie. "If markets are going to be efficient and effective and less volatile, we need to cage the cheetahs," Chilton said at the time. "I'm not saying they should be extinct, and overly burdensome regulations shouldn't endanger them as a species, but they need to be confined."
Chilton's speeches generally focused on the need for regulation and fairness in high-frequency trading, not the elimination of it.
Today, Chilton says his policy views have remained consistent in his new role. "The HFT guys don't particularly like that I called them cheetahs, but at the same time, it's not inconsistent with the policy I've always espoused," he said. And Chilton added that he is prepared to register as a lobbyist if his new role meets the legal threshold for doing so.
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Will he continue to refer to high-frequency traders as "cheetahs" from his new perch at DLA Piper?
"Probably not as much," Chilton said.
—By CNBC's Eamon Javers. Follow him on Twitter: @eamonjavers