Groups of angry investors descended on the Tehran Stock Exchange (TSE) on July 1 after suffering heavy losses on the shares of a firm which saw its share price triple in the past month, Tasnim News Agency reported.

Protesters hoisted banners against the company, Kontor Sazi, which makes electricity meters, chanted slogans and threw paper from the visitors' gallery down onto the main trading floor. An Iran Student News Agency (ISNA) report said TSE employees locked down the exchange as more angry investors attempted to enter it from Hafez Street. Reportedly, when police finally arrived on the scene after being called several times by TSE staff, many of the protesters fled.

Iranian stock market investors have become increasingly skittish in recent months with many of the leading TSE indices suffering suspensions for unknown reasons.

This latest outbreak of investor anger follows several protests mounted outside failing credit intuitions across the Iranian capital in recent weeks.

On May 17, the Caspian Credit Institution – which drew a protest of more than 1,500 people in Tehran in January – was given a licence to open 20 new branches as part of an effort to restore its brand and grow overall capital.

Unlicensed financial institutions grew under the 2005-2013 Ahmadinejad presidency, with the central bank struggling to shut them down. Customers began using them as they offered short-term savings accounts with interest rates of more than 26%, often 5% more than was offered by banks.