Is it permissible to sell a portion of an indivisible item (Mutaqawwim) previously acquired jointly and then divided, as a sale on Murabaha (cost-plus pricing)?

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The sale of a portion of an indivisible item, such as textiles, animals, or fruit-bearing trees, previously bought jointly and then partitioned, as a Murabaha sale based on its share of the original price is not permissible unless the full situation is disclosed. Ahmad bin Hanbal explicitly stated that anyone who buys something jointly with others and then divides it cannot sell his share via Murabaha unless he states: 'We bought it jointly, then we divided it.' This view is supported by Al-Thawri, Ishaq, and the Ahl al-Ra'i (Hanafi school). The primary reason for requiring disclosure is that dividing the price among the shares relies on mere conjecture (dhann wa takhmin), which carries a high probability of error. Since a Murabaha sale is a trust (amanah), such conjecture is impermissible. This situation is analogous to estimation (kharṣ) based on conjecture, which cannot be used in transactions requiring exact measure (tamathul). The justification for the Shafi'i principle regarding right of preemption (shuf'ah) in similar contexts does not apply here because a clear alternative exists: disclosing the situation or selling by negotiation (musawamah).