Can traders agree on prices before they submit their tenders?
Question

                Is it permissible for a group of traders to agree on prices before they submit their tenders, after they learn of the amount allocated for this particular deal, in order to prevent another trader undercutting them, and after one of them wins the deal, they will share it with one another.
Praise be to Allah.
    It is not permissible for the traders to agree on prices 
    before submitting their tenders, because that harms the one who is seeing 
    the deal, who only invited them to submit their tenders in order to get the 
    best deal. The Prophet  (peace and blessings of Allaah be upon him) 
    said: “Leave the people alone (to engage in trade), and Allaah will provide 
    for some of them by means of others.” Narrated by Muslim, 1522. Moreover, 
    agreeing in advance and sharing out the deal among the traders without the 
    knowledge of the agent is deceiving him, and in the hadeeth it says, 
    “Whoever deceives us is not one of us.” Narrated by Muslim, 101. 

    The Standing Committee was asked about buyers at an auction 
    agreeing not to increase the price beyond a specific limit. They replied: 

    The agreement between buyers to stop when the price at an 
    auction reaches a certain limit is a kind of selfishness, which will cause 
    harm to the sellers of the product. Both selfishness and harming others are 
    forbidden. This is a bad attitude that does not befit the Muslims and is not 
    approved of by Islamic sharee’ah. The seller who is affected by such a 
    conspiracy not to raise the price beyond a pre-set limit has the choice, if 
    he realizes that he has been cheated, of either annulling the sale or 
    allowing it to proceed. 

    Fataawa al-Lajnah al-Daa’imah, 
    13/114. 
The Muslim should strive 
    to ensure that his food comes from good, halaal sources. The Prophet  
    (peace and blessings of Allaah be upon him) said: “Every body that is 
    nourished from haraam sources, the Fire is more suited for it.” Narrated by 
    al-Tabaraani and Abu Na’eem from Abu Bakr; classed as saheeh by al-Albaani 
    in Saheeh al-Jaami’, no. 4519.

     It was also narrated by al-Tirmidhi, 614, from the hadeeth 
    of Ka’b ibn ‘Ajrah, where the wording is: “No flesh grows that was nourished 
    from haraam sources, but the Fire is more suited for it.” 

    May Allaah protect us and you from the evil thereof. 

    And Allaah knows best.