John Rose actually said...

"I would like to ask each of you, are there any unlikely but plausible black swan events that could pose a systemic risk to the global financial system?"

"I might just end by saying I know by definition I am asking you to think about the unknown unknowns."

"One of the major themes of this hearing are the risks of black swan events to the global derivatives markets."

"It seems that in the digital asset space, much of the friction, at least in the U.S., is between who would be the primary regulator."