Turkey's benchmark index fell by 229.79 points to open at 90,261.59 points on Monday.
On the first trading day of the week, the BIST 100 stock exchange declined by 0.25 percent while the banking and the holding sector indexes decreased by 0.32 percent and 0.23 percent, respectively.
Among the sub-indices, the informatics sector showed the greatest increase -- up by 0.87 percent in initial transactions -- while the leasing and factoring index started the day with the biggest decline, falling by 0.81 percent.
At Friday's closing session, the benchmark index was up by 0.25 percent to 90,491.39 points -- a 25-month high -- with a total trading volume of 4.1 billion Turkish liras ($1.1 billion).
The U.S. dollar/Turkish lira exchange rate rose to 3.6290 at 9.30 a.m. local time (0630GMT) on Monday, compared with 3.6170 at Friday's close.
Gold held at $1,234.35 an ounce. -