(Bloomberg) -- Investigators at a key US regulator have concluded that the co-founder of Voyager Digital Ltd. broke derivatives regulations before the failed crypto lender plunged into bankruptcy last year, according to people familiar with the matter.Most Read from BloombergThe Moral Case for No Longer Engaging With Elon Musk’s XThe 5% Bond Market Means Pain Is Heading Everyone’s WayAlmost Anyone Can Become the House Speaker, Except Donald TrumpIt's Done. The Future Is Battery-Powered Electric