The Depository Trust & Clearing Corp. is a financial-market utility that is owned by the big banks, brokers and mutual-fund companies and that helps them keep track of what they own and what they've sold to each other. They own lots of things, and are constantly selling those things to each other, so this is a hard job! DTCC can't just write the things down on index cards; it needs lots of computers to keep track of all the things. Sometimes outside companies write good programs to help computers keep track of things, and then DTCC buys those programs so that its computers can be good at remembering where all the things are. Yesterday DTCC announced that it will be using a new program to keep track of one class of things -- repurchase agreements -- that banks trade with each other.