Credit Suisse has cut the pay package of its former chief executive Tidjane Thiam by almost £2m after ousting him last month over a corporate espionage scandal.

In its annual report, the Swiss bank confirmed it had slashed Thiam’s short-term bonus by a third, taking his total pay packet for 2019 down to 10.7m Swiss francs (£9.2m).

The 57-year-old left the bank in February after a boardroom battle that erupted when the bank admitted hiring private detectives to track two of its executives. The former chief operating officer, Pierre-Olivier Bouée, has been blamed by Credit Suisse for both incidents.

Credit Suisse said that while its independent investigation found Thiam was not involved in the spying row, he was still accountable for the scandal and had accepted the pay cut.

“He has led by example in terms of personal commitment to the group’s conduct and ethics standards, but recognising that the observation matter had a significant impact on the group, his non-financial assessment score has been reduced,” it said.

Thiam is still being paid a base salary of about £250,000 per month until 31 August, when his notice period would have come to an end. His departure came just months after the scandal erupted in September 2019.

Iqbal Khan, the former head of the bank’s wealth management division, was trailed by private investigators for several days September, shortly after he left the bank for a rival position at UBS. It culminated in an erratic car chase through the streets of Zurich, where Khan eventually tried to confront the private detectives.

Rumours over Thiam’s involvement swirled amid reports that relations with Khan had soured. Simmering tensions between the two ambitious executives reportedly came to a head during a dispute over landscaping at their neighbouring properties near Lake Zurich.

Thiam has not been found guilty of any wrongdoing and Bouée, who was sacked weeks later, was the only executive blamed for the scandal. A private security consultant who had helped Bouée organise the spying reportedly killed himself after the incident.

At the time, Credit Suisse said it was a one-off case, but by December a second case emerged. The Swiss bank admitted that the former head of human resources Peter Goerke was followed for “several days” in February 2019 by private detectives who were hired on behalf of the bank.

The scandal has sent shockwaves across Switzerland’s famously secretive banking industry. But Credit Suisse tried to reassure investors that despite the damage to its reputation its business had not been affected.

“While we believe these events have not had any long lasting impact on shareholder value or affected our client relationships, certainly the level of media scrutiny and the potential damage to our reputation was concerning,”it said.

The bank is still being investigated by Finma, Switzerland’s financial regulator.