Ruling 2162
If the partner who conducts transactions with the partnership capital buys and sells in a manner that is contrary to the contract made with him, or if no contract was made with him and he conducts transactions in a manner that is not normal, then in these two cases, even though the transaction is valid based on a stronger opinion (aqwā),[1] if the transaction is detrimental to the partnership or part of the partnership’s property perishes, the partner who acted contrary to the contract or acted in a manner that was not normal is responsible (ḍāmin).
-Ayatullah Sistani, Practical Laws of Islam, Partnership (Shirkah)
1
For practical purposes, where an opinion is stated to be ‘stronger’, a fatwa is being given.