How much zakat is due on an Islamic financing amount, most of which was lost in trade, with a portion remaining as a debt owed by another person, in addition to another amount that was borrowed and used to purchase heavy equipment for the purpose of sale, which has not yet been sold after a year?

Zakat (definition) is obligatory upon anyone who possesses the nisab (definition), even if they are in debt. This is the view of Imam Shafi'i, Ibn Baz, and Ibn Uthaymeen.

As for debts owed to a person by others, if the debtor is wealthy and able to pay, then zakat on that debt is obligatory every year. It is permissible to delay the payment of zakat until the money is received, then one pays zakat for the past years. If the debtor is poor or denies the debt and there is no evidence to prove it, then there is no zakat on it. The more cautious approach is to pay zakat for one year upon receiving it, which is the view of the Malikis.

Whoever buys something with the intention of trade, and a year has passed, and it reaches the nisab by itself or by combining it with other money, then its zakat becomes obligatory by valuing it according to market price and paying one-quarter of one-tenth of its value.

Based on this, the questioner must pay zakat on the money in his possession, the money he has with his friend, and the value of the machine designated for sale, provided the conditions are met, without considering the debt he owes.