Gambling (Maysir, maisir; وَالْمَيْسِر or Qimar, قمار) as a game to spend money and expect larger outcomes was widespread practiced in the preislamic time of the Arabs. The Quran prohibited gambling alongside alcoholics in Sura Al Baqarah (Sura 2), Verse 219:
“They ask you concerning wine and gambling. Say: ‘In them is great sin, and some benefit for men, but the sin is greater than the benefit. […]”
Gambling differs from trade as what one receives is the other’s loss, it is a zero sum while trade exhange generates typically a win-win situation. There is some concerns among Muslims whether investing in stock market resembles gambling by nature; while the majority of scholars accepts trading of company shares as long as the companies are not involved in forbidden areas or involved in Riba. The reservation of some Muslims may remain, especially if they feel unconfortable regarding the proper intentions of themselves. In stock trading is a grey zone where investing ends and gambling starts which cannot be drawn precisely, but it is related clearly to the individuals intention, which is not be judged by legal analysis but by self control.