To­day, when in­vestors buy stock, they use a bro­ker, who holds the client’s as­sets at a cus­tody bank. The trade is pro­cessed by an ex­change. A clear­ing-house called the De­pos­i­tory Trust & Clear­ing Corp. is the ac­tual holder of every pub­licly is­sued stock in the U.S. Ul­ti­mately, every trade is pro­cessed by the DTCC. The amount of time it takes a stock trade to wind its way through that pipe­line is about two days. Every fi­nan­cial in­ter­me­di­ary main­tains their own set of records, and “back of­fices” on Wall Street and around the world spend a lot of time and ef­fort rec­on­cil­ing dif­fer­ent record books. – wsj