Hawzah News Agency – Some disapproved transactions are as follows:

-  selling real estate, unless one buys another real estate with the money acquired from the transaction;

-  to be a butcher;

-  selling shrouds (kafans);

-  transactions with people of low character;

- transactions between the start of the time for the morning (ṣubḥ) prayer and sunrise;

-  making one’s profession the buying and selling of wheat, barley, and suchlike;

- intervening in someone else’s transaction in order to buy the goods that the other person wishes to buy.

Source: https://www.sistani.org/english/book/48/