Did I read somewhere that it is best to buy an Savings Bond on the last day of the month? Also, do you need to put on a beneficiary? I am sending a bond to my son, who is not married. If he should pass away how are these bonds cashed? Tom's response When you buy a Savings Bond, you will earn interest for the entire month of purchase no matter which day of the month you buy it on. So you get the equivalent of a free month's worth of interest if you purchase on the last day of the month. If there's no co-owner or beneficiary listed on a Savings Bond and the owner dies, the bond becomes part of the person's estate and is distributed according to his will. If he doesn't have a will, state law determines how his estate is distributed. The exact process for cashing the bond will depend on the exact circumstances. There are complete details in my book.