Tehran Stock Exchange (TSE) index is declining rapidly; losing 6.2% of its value last week and on Thursday registered the largest single-day decline in 2.5 years. TSE value had been rising as rapidly for more than a year. A number of analysts believed that the rise in the value of TSE was real and tied to the actual production of its member companies and the country’s GDP in general. Others believed the market represented a dangerous bubble, ready to burst anytime. The performance of TSE in the next few weeks should validate the correctness of one of these analyses.