THE NEW TITANS OF FINANCE prowl a glass fortress 3,000 miles from Wall Street. High above San Francisco’s Market Street, their headquarters take up three floors with sweeping views of the bay and city below. The reception desk bears jars brimming with chocolate coins near a jokey “Initial Chocolate Offering” sign. Beyond it, in an open space with no corner offices, big shots poached from Silicon Valley giants sit beside junior hires clutching free cans of LaCroix. This is the home base of Coinbase, the buzzy startup that wants to rewire the financial system around blockchains and digital currency.