Turkey's stock exchange fell 0.11 percent, or 114.97 points, to open at 102,794.16 points on Friday.
On the last transaction day of the week, the banking sector index rose 0.11 percent and the holding sector index lost 0.11 percent.
Among all sector indices, the tourism sector index posted the best performance, up 0.68 percent, while the chemical, petrol, plastic sector index suffered the worst drop, down 1.43 percent.
On Thursday, Borsa Istanbul's BIST 100 closed at 102,909.13 , down 1.73 percent, or 1,816.61 points, with a 7 billion Turkish liras ($1.67 billion) trade volume.
The U.S. dollar/Turkish lira exchange reached 4.2420 as of 9.30 a.m. local time (0630GMT) on Friday. It was 4.2100 at Thursday's close.
The euro/lira exchange rate rose to 5.0770 by market open — from 5.0430 at the previous close — and one British pound traded for 5.7590 Turkish liras versus 5.7320 at the previous close.
The price of Brent oil stood at $73.57 per barrel as of 10.00 a.m. local time (0700GMT) Friday, compared to $73.62 on Thursday.