Turkey's benchmark stock index fell 0.34 percent or 314.39 points to open at 91,072.14 points on Friday.
On Thursday, Borsa Istanbul's BIST 100 index rose 1.48 percent to close the day at 91,386.52 points with a daily trading volume of 6.7 billion Turkish lira ($1.25 billion).
The U.S. dollar/Turkish lira exchange rate increased to 5.3650 as of 9.30 a.m. local time (0630GMT), compared with Thursday's closing rate of 5.3360.
The euro/lira rate was 6.0950, versus 6.0700 at the last close. One British pound was exchanged for 6.7870 Turkish liras, as the GBP/TRY was 6.7770 by market close on Thursday.
The price of Brent oil was around $61.09 per barrel as of 10.10 a.m. local time (0710GMT) Friday.
Source: Anadolu Agency