But none of the statutory boards - including the MAS - invested in notes that have now become worthless, such as DBS High Notes 5 and Merrill Lynch Jubilee Series 3 LinkEarner Notes.

The central bank had invested only 0.1 per cent of its portfolio in such investments, which in fact made a net gain over the past year.

A Ministry of Finance (MOF) spokesman, who revealed this to The Straits Times on Tuesday, did not give the actual size of the investment.

He was responding to queries after Finance Minister Tharman Shanmugaratnam told Parliament that five statutory boards had invested in credit-linked notes, but only named four: Singapore Civil Service College, Singapore Land Authority (SLA), Infocomm Development Authority of Singapore (IDA) and Professional Engineers Board.

Mr Tharman had emphasised in Parliament that the four boards had invested in credit-linked notes, but not the ones which have gone into default or suffered credit events that have caused their value to plummet to zero and triggered early redemption.

The notes that have suffered this fate include Lehman Minibonds, Merrill Lynch Jubilee Series 3 LinkEarner Notes, DBS High Notes 5 and Morgan Stanley Pinnacle Series 9 and 10 Notes.

Although he did not provide the actual amount invested by each of the four named statutory boards, he said that the exposure as a percentage of their total combined investment portfolio was only about 0.05 per cent.

These investments are currently suffering paper losses of about 14 per cent over the past year, he added.

'On a mark-to-market basis, these credit-linked notes held by the four statutory boards have not performed very differently from the performance of global markets generally this year,' he said.

'The four statutory boards are nevertheless monitoring the situation on all their investments, and will take the necessary steps to minimise any losses in these investments.'

MOF later told The Straits Times that the four statutory boards have had positive returns on their overall investment portfolios this year, averaging about 2 per cent.

And for the past three years, the average annual return on their investment portfolios had averaged 3 per cent.

Mr Tharman was responding in Parliament on Tuesday to questions from Non-Constituency MP Sylvia Lim, who asked whether statutory boards had invested in risky structured products which were linked to bankrupt United States investment bank Lehman Brothers.

Read the full story in Wednesday's edition of The Straits Times.