The peculiar Turkish corruption issue behind Istanbul mayor’s arrest – and how it became a tool of political oppression

Turkey is in turmoil after Istanbul’s mayor, Ekrem Imamoglu, a leading opposition figure and potential challenger to Turkey’s president, Recep Tayyip Erdogan, was arrested on March 19 on charges of corruption.

More than 1,000 people who protested against the arrest have also been detained as hundreds of thousands of demonstrators took to the streets in anger at what they say is a major blow against democracy. Imamoglu, who denies all charges against him, has since been endorsed as the candidate for the 2028 presidential elections for the Republican People’s Party (CHP).

Central to the allegations of corruption is what is known in Turkey as “naylon faturacilik”. This literally means “nylon invoicing” and refers to the issuing of fake invoices. It doesn’t refer to simple clerical errors or accounting mishaps, but deliberate attempts to fabricate transactions, inflate expenses, or obscure real beneficiaries.

Technically illegal, the practice is nonetheless widespread in Turkey. It forms part of what many see as the country’s informal economy.

The informal economy in Turkey spans everything from street vending and informal recycling to complex tax evasion schemes involving registered firms. Naylon faturacilik illustrates how corruption doesn’t always sit outside the system, but often thrives from within it.

It exposes a blurry boundary between formal and informal economic activity, revealing how some formal businesses manipulate legal frameworks to appear compliant while engaging in illicit practices. In September 2024, Turkey’s Ministry of Finance uncovered 3 billion Turkish Lira (£61 million) worth of fake invoices in an investigation targeting around 4,500 large taxpayers.

Over the past four years, I’ve interviewed more than 60 business owners, workers, and entrepreneurs across Turkey – from informal micro-enterprises to firms embedded in formal supply chains. One theme surfaced again and again: naylon faturacilik, or fake invoicing.

People described it not as an exception but as “just part of doing business” in an informal economy. In an economy shaped by patchy enforcement and institutional fragility, this practice has become normalised over the past decade. It’s not legally accepted, but has unfortunately become socially expected.

Under Turkish law, issuing or using fake invoices is a serious offence, punishable by three to eight years in prison. Yet many of my interviewees, especially those operating in or alongside the informal economy, saw fake invoicing as a necessary way of doing business. They described it as a viable response to rising costs, bureaucratic hurdles and a system that often punishes formality.

Read more: Turkey: a favourable international climate is spurring Erdogan’s crackdown on democracy

Opposition leaders, including CHP leader Özgür Özel, argue that Imamoglu’s arrest is politically motivated – an attempt to discredit their candidate ahead of the presidential election. Özel condemned the operation as a “coup attempt” against Turkey’s democratic future.

In a press conference, he revealed that most of the people detained alongside Imamoglu are linked to companies that won public contracts from the Istanbul Metropolitan Municipality (IBB) under the control of Imamoglu. Moreover, some of those arrested, he claimed, are students or relatives with no actual involvement in procurement decisions or public bids.

The key accusation is that these companies issued fake invoices – billing for work never done, or for services exaggerated or duplicated. Yet Özel contends that no concrete evidence has been presented thus far and much of the government’s case comprises testimony and vague associations from gizli tanik (secret witnesses).

One such witness reportedly named a communications or media firm that had worked with both IBB and the central government – including on campaigns commissioned by the presidency’s Directorate of Communications that work directly with Erdogan. When the same activity, individuals or businesses, can be framed as legitimate under one administration and criminal under another, the line between legality and politics becomes dangerously thin.

While opposition mayors in Turkey face swift legal action against corruption, serious corruption allegations against former Ankara mayor Melih Gökçek, which he denies, involving nearly 46 billion Turkish lira in public losses remain uninvestigated. Gökçek was a member of Erdogan’s government Justice and Development Party (AK).

A total of 97 complaints were filed over alleged misconduct during Gökçek’s tenure as mayor of Ankara until 2017, but nothing was done. Critics say this reflects politically selective justice.

One law for some

This isn’t just a story about fake invoices. It is about contexts where rules are unevenly enforced, where legal grey zones are abundant and where informality becomes a flexible instrument of control. A practice such as naylon faturacilik tolerated in one political moment can become a liability in another. A company can operate legally while it enjoys good relations with the government – and suddenly find itself under suspicion when that changes.

In Turkey today, the question is often not whether an act is legal or illegal. It’s more about who is involved and whose power is being threatened. The lines between formal, informal or illegal is not merely economic – it is profoundly political. That’s why the nylon invoicing issue is so revealing. Far from being a fringe practice, it exposes the everyday intersections of power, legitimacy and corruption.

In a climate of deepening polarisation and eroding institutional trust, many believe that who gets punished for corruption depends less on the act itself and more on which side of the political divide they fall.

Turkey’s democracy and justice system are being tested – not only by corruption, but by how selectively corruption is investigated and enforced. In this uncertain moment, the challenge is not only to hold people accountable, but to rebuild trust in institutions and ensure that justice is applied fairly. The protestors’ slogan “hak, hukuk, adalet” (rights, law, justice) carries a deeper warning: power is temporary, but justice must endure.

As many demonstrators in Turkey are now reminding the Erdogan government: when the balance shifts, those in power today may find themselves in need of the very fair and independent legal system they are now so determined to undermine.

Tulin Dzhengiz research on the informal economy received funding from Manchester Metropolitan University.