By Gokhan Ergocun
Turkey's benchmark stock index fell 0.94 percent to close at 90,528.64 points on Friday.
Borsa Istanbul's BIST 100 index dropped 857.88 points from Thursday's close of 91,386.52 points, while it started the day at 91,072.14 points.
On the last transaction day of the week, the BIST 100 peaked at 91,201.04 points, while its daily low was 89,337.50 points.
With a trade volume of 4.6 billion Turkish liras ($857.9 million), the BIST 100's total market value was around 588.2 billion liras ($109.7 billion) at close.
Private lender Garanti, national flag carrier Turkish Airlines, and defense company Aselsan posted the highest trade volumes on Friday.
Compared to Tuesday's close, 21 stocks on the BIST 100 rose, 77 declined, and two were flat.
The shares of energy and construction company Isiklar Enerji Yapi Holding posted the best performance on Friday -- up 19.51 percent -- while stocks of private lender ICBC Turkey Bank did the worst, losing 19.96 percent.
The U.S. dollar/Turkish lira exchange rate reached 5.3930 at close, up from Thursday's close of 5.3360.
The euro/lira rate also increased at close to 6.0840, compared with 6.0700 at the previous close.
And the British pound/lira rate showed no change compared with Thursday's close of 6.7770.
In Borsa Istanbul's Precious Metals and Diamond Markets, the price of one ounce of gold was around $1,239.00 by market close, down from $1,242.70 the previous day.
The price of Brent crude oil rose to $60.72 per barrel as of 6 p.m. (1500GMT) Friday, versus $60.48 at the previous close.