Is it permissible to complete a business deal with a foreign company if the deal involves paying a percentage of money to an official in the company through an intermediary, knowing that this percentage is an increase over the agreed-upon price and will be paid outside the company's framework, and is this act considered bribery?

Your friend's dealing with the company's sales manager by increasing the price and taking the difference for himself is considered bribery and a great betrayal of the company. It is not permissible to proceed with this transaction, for Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." Also, one must seek lawful earnings and keep away from forbidden things and doubtful matters, for the Prophet, peace and blessings be upon him, said: "The lawful is clear and the unlawful is clear, and between them are doubtful matters." And whoever fears Allah, He will make his provision easy for him, for Allah Almighty says: "And whoever fears Allah - He will make for him a way out and will provide for him from where he does not expect."