
Tharit Pengdit, secretary-general of the office, said preliminarily it was found that in the middle of 2008, the fund's assets stood at Bt376 billion but Bt74 billion was wiped out in the last four months of the year.
The fund manages pensions for 1.1 million civil servants.
Tharit urged the fund to explain to civil servants, why it suffered from huge losses though it is required by laws to invest in safest instruments. As the state agency, it should shoulder responsibility, he said.
The office's investigation will call for cooperation from the Securities and Exchange Commission and capital market experts.
The Government Pension Fund earlier attributed the loss to the global economic crisis.