Time plotting

A survivor's option bond (or certificate of deposit) is a bond (or CD) that can be held by two people in a joint account, and if one of them dies, the bond can be redeemed immediately at par. Many of these bonds traded at a discount to par, and Lathen had the bright yet also undeniably dark idea of finding terminally ill people (in hospices and nursing homes), buying discounted survivor option bonds jointly with them, and then redeeming them at par when the people died. This worked quite well, and Lathen ended up setting up a hedge fund to run the strategy using investor money.

Issuer of CD  being quite dumb.