The number of people detained on Tuesday after simultaneous raids on 51 companies suspected of supporting the Fethullah Terrorist Organisation (FETO) has risen to 80.
Financial crime officers in Istanbul raided companies suspected of providing financial help to the terrorist network, a security source said.
Companies, including Akfa Holding and the A101 supermarket chain in the Uskudar and Umraniye districts, were raided with backup from riot police.
A security source told Turkish media that arrest warrants were issued for 120 people, of which 50, including Fatih Aktaş, chairman of Akfa Holdings, were detained.
Police said seven remaining suspects were abroad.
The detainees who were working at Akfa Holding allegedly helped ‘himmet money’ transfers between 2011 and 2015 via Bank Asya to organisations in the US and Canada.
‘Himmet’ refers to money collected as charitable donations from followers of FETO.
On July 22, Turkish regulators cancelled Islamic lender Bank Asya's banking license.
Bank Asya is a participation bank affiliated with US-based preacher Fethullah Gülen.
A wave of detentions following the July 15 coup attempt has seen around 26,000 people arrested across Turkey.
Senior business figures, as well as members of the military, police, judiciary, prosecutors and teachers, have been among those targeted.
Turkey's government has said the defeated coup, which left 240 people martyred and nearly 2,200 injured, was organised by members of FETO.
Gülen has been living in self-imposed exile in Pennsylvania since 1999.
Gülen is accused of leading a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary, forming what is commonly known as a parallel state.