What is the ruling on lost money whose owner cannot be reached?

If someone finds another's property that has value, they must publicize it. As for something that has no value, it is not obligatory to publicize it, and it is permissible to take it.

Determining what is considered 'trivial' (Yaseer): Imam Ahmad held that the criterion for this is common custom (urf). Malik and Abu Hanifa, however, held that it is what does not warrant cutting off the hand of a thief (a quarter of a dinar according to Malik, and ten dirhams according to Abu Hanifa). The most preponderant opinion is that there is no specific determination. It is permissible to take a whip, a stick, a rope, and items of similar value.

The preference regarding picking up lost property: Ahmad preferred leaving it, while Shafi'i held that it is better to take it if it is in a place where it might be lost and the finder is confident in their ability to safeguard it. Abu Hanifa held that it should be taken.

If lost property is taken, it is obligatory to publicize it for one year in public places. If it is not claimed, the finder owns it, but they are liable to its owner whenever the owner appears.