Gharar

Abu Hurairah narrated that the Messenger of Allah prohibited "the gharar sale," a hadith recorded in Sahih Muslim (1513). Classical jurists such as Ash-Shafi'i illustrated the principle with concrete examples: selling fish still swimming in the water, birds still flying in the sky, a runaway slave, or fruit before it is visibly formed on the tree. In each case, the buyer cannot be sure the seller can actually deliver what was sold, or even be sure exactly what they are getting.

Not all uncertainty is banned; ordinary commerce always carries some risk about future prices, demand, or outcomes, and that ordinary risk is tolerated. The prohibition targets excessive uncertainty (gharar fahish) that turns a sale into a bet on an unknown outcome, where one party can only gain because the other is left genuinely in the dark. Minor, unavoidable uncertainty, such as not knowing the exact weight of produce sold by reasonable estimation, is tolerated; scholars distinguish between degrees of uncertainty rather than banning uncertainty outright.

Several modern financial practices are debated on gharar grounds. Naked short-selling, selling shares one does not own or has not borrowed under clearly defined terms, is contested because the seller's ability to deliver is uncertain. Some options and derivatives structures are flagged because the underlying obligation, price, or delivery mechanism is highly speculative. Conventional insurance is also contested partly on gharar grounds, since the payout is tied to an uncertain future event with no clear, agreed exchange, alongside separate riba and maysir concerns; this is part of why takaful was developed as a cooperative alternative.

Buying a share of common stock, an ownership stake in a real, existing business, priced through known and transparent market mechanisms, is not gharar. That is why plain equity ownership passes this screen regardless of how volatile the stock's price may be; price volatility is market risk, not contractual ambiguity about what is being exchanged. Where gharar becomes genuinely relevant is in how an investor trades around the stock: options, margin-based short selling, and other derivative structures layered on top of the stock, rather than the underlying share ownership itself, are the parts scholars flag for closer review.