The BIST 100 index on Borsa Istanbul fell 43.69 points, or 0.30%, from the previous close to 14,457.80 points.
The index had ended the previous trading day at 14,501.49 points, down 0.09%. At the opening, the banking index fell 0.06%, while the holding index declined 1%.
Sector indices in focus
Forestry, paper and printing was the top gainer among sector indices, rising 1.29%. The information technology index recorded the sharpest decline, falling 3.19%.
Global risks remain in focus
Risk appetite is being limited by the escalation of US-Iran tensions into economic sanctions, concerns that tariff wars could flare up again and questions surrounding the US plan to intervene in the bond market.
As the indirect effects of geopolitical tensions in the Middle East on global economies continue, the failure to reach an expected agreement between the United States and Iran and the escalation of their disputes into economic sanctions are influencing the course of asset prices.
Busy data agenda abroad
While the domestic data agenda is expected to remain calm, markets will follow a busy stream of data from the United States, led by the house price index and the New York Fed's consumer confidence index.
Technically, 14,400 and 14,300 points are being watched as support levels for the BIST 100 index, while 14,600 and 14,700 points are seen as resistance levels.