Borsa Istanbul's 6-week decline streak melts away market value

Amid a crisis of confidence triggered by a fund crisis, Borsa Istanbul experienced a continuous decline for 6 weeks between September 11 and October 23, 2026, recording the longest losing streak in its history. While the index dropped from 14,467 points to the 11,116 level, a loss of 6.7 trillion liras occurred in the total market value.

The index, which stood at 14,467 points on September 11 in the stock market, declined to the 11,116 level as of October 23. While the index made its lowest close since December 5, 2025, the total loss over the 6-week period was 23.16 percent.

While the loss in the BIST-30 index remained at the level of 19.5 percent, the BIST YUZO Index, formed by removing BIST 30 companies from the BIST 100, lost 34.4 percent in value, and the BIST TUMY Index lost 49.78 percent. The total market value of companies dropped from 20 trillion 832 billion liras to 14.1 trillion liras.

Investors' losses in the publicly traded portion exceeded 1.8 trillion liras, and their losses in dollar terms exceeded 39.4 billion dollars. In the week of October 19-23, 79 different companies carried out share buybacks, while since September 11, the decline in 135 stocks exceeded 50 percent. In BIST 30, the highest decline was seen in Astor with 50 percent, and the lowest loss was seen in TAV with 2 percent.