Is it permissible to share a target bonus with a colleague who was helped in achieving it?

The answer addresses two issues: First: The ruling on 'Tarajat' (tasks/jobs) and the resulting compensation. This falls under the category of 'Ja'alah' (reward/stipend). If the compensation is known and specified, then the 'Ja'alah' is valid by consensus. However, if it is a percentage of an unknown entity, the majority of jurists deem it invalid, while some consider it valid. In the case of invalidity, the 'wage of the like' (ajr al-mithl) is due.

Second: The ruling on you and your colleague splitting the compensation. If these 'Tarajat' are specific to the company you both work for, then the compensation belongs to the company. It is not permissible for either of you to take anything from it except with the company's permission; otherwise, it would constitute a breach of trust and unlawful consumption of people's wealth, based on the Almighty's saying: "O you who have believed, do not betray Allah and the Messenger or betray your trusts while you know" [Al-Anfal: 27], and His saying: "O you who have believed, do not consume your properties among yourselves through falsehood except that it be trade by mutual consent from you" [An-Nisa: 29].

However, if these 'Tarajat' are specifically for the assigned workers, and you and your colleague are among them, and you helped your colleague, then there is no harm in splitting it according to your agreement. If your colleague is the primary assigned worker and you helped him: If the assistance was outside working hours, there is no harm in taking what you are entitled to from these 'Tarajat'. However, if it was during working hours, it is not permissible to take anything except with the company's permission.