Turkey's benchmark stock index dropped by 1.22 percent to close at 92,827.29 points on Thursday.
Borsa Istanbul's BIST 100 index started the day at 93,506.84 points and lost 1,142.87 points from Wednesday's close of 93,970.16 points.
During the fourth transaction day of the week, the BIST 100 peaked at 93,866.56 points, while its daily low was 92,375.25 points
Turkish conglomerate Koc Holding ($7.14 billion), private lender Garanti Bankasi ($6.1 billion), and energy company Tupras ($5.85 billion) were the most valued listed companies.
Garanti Bankasi, national flag carrier Turkish Airlines, and private lender Akbank posted the highest trade volumes on Thursday.
Compared to Wednesday's close, 28 stocks on the BIST 100 rose, 65 declined, and seven were flat.
Shares of furniture manufacturer Dogtas Kelebek Mobilya were the top gainers, up 7.08 percent, and shares of casting producer Cemas Dokum were the worst, losing 19.50 percent.
The U.S. dollar/Turkish lira exchange rate reached 5.3690 at
The euro/lira rate also increased at
One British pound was traded for 6.8620 Turkish liras, while the GBP/TRY rate was 6.7970 at close on Wednesday.
In Borsa Istanbul's Precious Metals and Diamond Markets, the price of one ounce of gold was around $1,236.75 by market close, down from $1,238.20 a day ago.
Brent crude oil price was $60.02 per barrel as of 6 p.m. (1500GMT) Thursday, versus $62.39 at