A finder of a lost object that will deteriorate over time is required to sell it and the money belongs to the owner of the object (saved for later when he claims his object.) In the meantime, the finder can use the money. He is considered to be like ne who borrows someone else’s object, and so if he loses the money under any circumstances he has to repay. Bava Mezia 28b and 29 a. This is like Rav Joseph who holds one who guards a lost object is not required to give charity at the time he is involved in his guard obligation. Therefore, he is like a paid guard, and then because he also can use the money, he gets stepped up one notch to be a borrower of the money who has a greater degree of responsibility to guard the money. This is how the Rabbainu Chananel and Rambam decided the law. {Tosphot disagrees holds he is like an unpaid guard like the decision of Raba.} This conflicts with Bava Metzia page 23 where you have a case of a person who deposited a untied bundle of money with a money changer. There since the money changed can use the money, he has the category of a paid guard who is liable if the money was lost by theft, but not liable for unavoidable things like if the boat it was on sank. This is how Rav Nachman decided the law and the Rambam decided in that case like Rav Nachman. [The problem is permission to use the money in one case (finder) makes him a borrower, and in the other into a paid guard.] The reason is given by Rabbainu Ephraim and the Magid Mishna that the guard of the money of the lost object has to levels stepped up from an unpaid guard to a borrower because he gets the benefit of not having to give charity while involved in guarding and taking care of the object and then also, he gets permission to use the object. Rav Shach suggested that guarding the lost object is required by Torah, and so that makes him more liable. However this answer seems difficult. The reason is that the difference between a paid guard and a borrower is that all benefit goes to the borrower while in the case of a paid guard, the owner of the object gets some benefit, That is after all why he is paying thee guard. But in both of our cases here some benefit goes to the owner of the money and so in both cases the guard should be a paid guard, not a borrower The only reason he could become a borrower is that he gets extra paid but benefit still come to the owner of the lost object. just because ethe Torah requires him to guard thee lost object that does not means that no benefit comes to the owner. after all the only reason the Torah requires the finder to guard the money of the sake of the object is for the benefit of the owner of thee lasts object. However I ca see the idea that since the torah requires him to guard the lost object tah t makes ahigher degree of responsibility. -------------------------------------------------------------------------------------------------------------------------------A finder of a lost object that will deteriorate over time is required to sell it and the money belongs to the owner of the object (saved for later when he claims his object.) In the meantime, the finder can use the money. He is considered to be like ne who borrows someone else’s object, and so if he loses the money under any circumstances he has to repay. בבא מציעא כ''ח ע''ב כ''ט ע''א and 29 a. This is like רב יוסף who holds one who guards a lost object is not required to give charity at the time he is involved in his guard obligation. Therefore, he is like a paid guard, and then because he also can use the money, he gets stepped up one notch to be a borrower of the money who has a greater degree of responsibility to guard the money. This is how ר' חננאלand הר''ם decided the law. {תוספות disagrees and holds he is like an unpaid guard like the decision of.} This conflicts with בבא מציעא מ''ג where you have a case of a person who deposited a untied bundle of money with a money changer. There since the money change can use the money, he has the category of a paid guard who is liable if the money was lost by theft, but not liable for unavoidable things like if the boat )it was on( sank. This is how רב נחמן decided the law and the רמב''ם decided in that case like רב נחמן. [The problem is permission to use the money in one case (finder) makes him a borrower, and in the other into a paid guard.] The reason is given by רבינו אפרים and the מגיד משנה that the guard of the money of the lost object has to levels stepped up from an unpaid guard to a borrower because he gets the benefit of not having to give charity while involved in guarding and taking care of the object and then also, he gets permission to use the object. Rav Shach suggested that guarding the lost object is required by Torah, and so that makes him more liable. However this answer seems difficult. The reason is that the difference between a paid guard and a borrower is that all benefit goes to the borrower while in the case of a paid guard, the owner of the object gets some benefit, That is, after all, why he is paying thee guard. But in both of our cases here some benefit goes to the owner of the money and so in both cases the guard should be a paid guard, not a borrower The only reason he could become a borrower is that he gets extra paid but benefit still come to the owner of the lost object. Because the תורה requires him to guard the lost object, that does not mean that no benefit comes to the owner. After all, the only reason the תורה requires the finder to guard the money of the sake of the object is for the benefit of the owner of thee lasts object. However I can see the idea that since the תורה requires him to guard the lost object that makes a higher degree of responsibility.