Is the buyer's profit permissible (halal) or impermissible (haram) in a case where the General Manager sells used company equipment to an employee for a price significantly lower than the market price, after asking him to bring two quotations lower than his own to obtain management approval, with the management knowing that the manager is implementing the system but being unaware that the buyer is an employee?

This is cheating, betrayal, and cooperation in sin and aggression, which the Qur'an and Sunnah (definition) have forbidden, as Allah Almighty says: "Do not betray Allah and the Messenger or betray your trusts" and "Cooperate in righteousness and piety, but do not cooperate in sin and aggression," and the Prophet, peace and blessings be upon him, said: "Whoever cheats us is not of us." The official who sells equipment at fictitious prices, colluding with an employee or someone else, is considered to have betrayed the trust and is liable for the shortfall in the price of the cars. The employee who colludes with him must repent, and what he gained from that transaction is considered unlawful wealth, and he is liable for the shortfall in the price. The company may claim from whichever of them it wishes.