Prohibition of trading in debt, i.e., sale of debt for debt, to me is more relevant in the modern financial markets than the plain vanilla prohibition of Riba. In fact, both are same and one thing, if looked into carefully. I still continue to come across views arguing against unambiguous ban on interest. This surprises me. It is even more surprising for me to find people who don’t take the prohibition of trading in debt seriously. Many books on Islamic finance don’t even mention it amongst the fundamental differentiators between Islamic and conventional finance. The raison d'être for the prohibition of sale of debt for debt is Sadd al-Drai’a (سدالزراۂع) . If not prohibited, it could have easily been used to structure deals in which two parties may apply premium or discount to their respective debts before trading in them. If done so, it would fall under the prohibition of Riba.