Hakim ibn Hazm is the principal narrator of a hadith that has become very important is the development of contract law in Muslim nations. His father was Hizam ibn Khuwaylid. Hizam was a merchant, who asked the prophet Mohammed whether it was permissible for him to sell to a customer goods that he doesn't yet possess ("short selling" in Western parlance). Mohammed forbade that.
Short selling often has a speculative element, which may be the reason for the prohibition. If Abdul sells to Tariq some cattle deliverable in 90 days, at today's cattle price, then Abdul is speculating that cattle will decline in price over those 90 days, so he can buy it at the lower price in 89 days, deliver it to Tariq then, and pocket a profit. Tariq is making the contrary speculation.
Other forms of activity that might be calling "selling what is not with you" involve options and futures contracts.
The author of Sahih Muslim states that Hizam had the unusual distinction of being born in the Kaaba, and lived 120 years. (ref)
