For some two decades mutual distributed ledger technology adoption has been held back by concerns over complexity and security. However, the enormous technical success of Bitcoin’s blockchain since 2009 has unleashed a torrent of innovation in banking, insurance, and trading, ranging from OTC derivatives clearing, to motor policies, to Know-Your-Customer/Anti-Money-Laundering applications, all using distributed ledgers. We will explain what a mutual distributed ledger is; what can these ledgers do; how do these ledgers affect trusted third party roles, such as banks, exchanges, lawyers, and accountants; what are the promises and perils in the brave new world of smart contracts, colored coins, and cryptocurrencies; and how might traditional financial services firms and their regulators respond, particularly to the possibilities ledgers without tokens or coins afford.