The 53-year-old mayor - Erdogan's main political rival - was arrested on March 19, days before he was announced as the candidate of the ruling National Democratic Party (CHP) party for the 2028 presidential race.

On 19 March, the BIST 100 index had already fallen 8.7 percent following Imamoglu's arrest on charges of "corruption" and links to a "terrorist organisation".

The damage was limited to a 0.5% drop the next day, but facing a sharp decline on March 21, trading was halted twice in the morning.

During Friday trading, the index fell below 9,000 points for the first time since early November, a decline of more than 16.5% in five days.

Imamoglu's party condemned his arrest as a "coup" and international organisations, including the European Union, expressed concern.

It also sparked street protests, which President Recep Tayyip Erdogan condemned as "street terror". | BGNES