The BIST 100 index lost 293.58 points to open at 77,100.11 on Wednesday morning during its first transactions.
The benchmark index decreased by 0.38 percent on the third trading day of the week. The banking and holding sector indices declined by 0.33 and 0.45 percent respectively.
Among all the sector indices, the basic metal sector index saw the biggest drop, 0.81 percent, in initial transactions.
The U.S. dollar/Turkish lira exchange rate accelerated to 3.8570 at 9.30 a.m. local time (0630 GMT) on Wednesday, compared with 3.7770 at Tuesday's close.
Gold held at $1,189.38 an ounce.
U.S. crude futures slightly increased by 0.24 percent to stand at $50.94 a barrel, while benchmark Brent crude futures rose by 0.15 percent to reach $53.72.
Anadolu Agency
