The investors pulled 4.6 billion liras ($790 million) out of the Istanbul Stock Exchange since December to reduce their holdings by 31 percent to 10.2 billion liras, Dünya said.
Qatar, a key regional ally of Ankara, pledged to increase its investments in Turkey at the height of a currency crisis last summer. In August, it agreed a $3 billion currency swap deal with the Turkish central bank to help the country shore up its financial system.
Qatari Emir Sheikh Tamim bin Hamad Al-Thani visited Ankara in August in an apparent show of support for Turkey, pledging $15 billion in direct investments in the country. There has been no news of further investments by the Gulf state since the swap deal.
The lira dropped 28 percent against the dollar last year after investors fretted over an overheating economy and a political crisis between Turkey and the United States over the detention of a U.S. pastor. The currency has declined a further 9.1 percent in 2019.