Tocom was forced to suspend trading on 12 May after a defective router led to connectivity failure. The router was replaced a couple of days later and sent for analysis at the manufacturer's laboratory to determine the cause of the malfunction.

The exchange is awaiting an analysis report from NTT Data, the systems integrator for its new trading platform. Tocom only went live with the system - for which Nasdaq OMX provided the technology - on 7 May.

Tocom says that while the primary cause of the trading suspension is still being investigated, "Nangaku recognises his responsibility as the head of Tocom for causing suspension of the session despite Exchange's duty of providing stable market functions".

Just days after the trading suspension the exchange was hit by market quotation disruptions when a malfunction with its uploading program stopped data being updated.

Nangaku follows in the footsteps of executives at fellow Japanese bourse, the Tokyo Stock Exchange, who have repeatedly had their pay slashed after systems glitches.

Last August the TSE said the wages of chairman Taizo Nishimuro and president and CEO Atsushi Saito would be slashed by 30% for one month. Senior MD and COO Yasuo Tobiyama and MD and CIO Yoshinori Suzuki each saw their pay cheque cut by 20% for a month.

Earlier that year a malfunction with the derivatives system forced TSE to halt trading in March futures contracts for the Topix index. That incident resulted in the salaries of Nishimuro, Saito, Tobiyama and Suzuki being cut by 10% for one month.

The exchange also slashed the pay of its then president and CEO Takuo Tsurushima and nine other senior executives following an incident in November 2005 when a problem with a software upgrade halted trading at the TSE for more than four hours. Fujitsu also cut the salaries of its president and six other top executives following its role in the systems crash.