1,225. Depositing Money
187:5 When a person finds an object and he doesn't know who lost it, whether or not it has an identifying mark on it, there are many detailed laws as far as how to proceed. Therefore, one must consult with a Torah authority about his course of action.
188:1 Regarding one who deposits money with his fellow, nowadays we are all engaged in commerce and everybody needs money, so we assume that the depositor want the one holding the money to make use of it as needed. Therefore, it is permitted for the one holding the funds to use them and it is considered like a loan. However if the depositor did something to indicate that he didn't want the money to be used, such as if he sealed it or tied it with a knot that he would recognize, then the one holding the money may not use it.