Accounts filed by the biggest trade union in the State show that its pension fund is €31 million in the red.

Returns filed by Siptu with the trade unions' financial regulator, the Registrar of Friendly Societies, show that it had an estimated deficit in its pension fund of €31 million on January 1st this year.

A note to the accounts states that the union operates a defined benefit pension scheme for its staff. Under these schemes, contributors are paid a sum linked to their pay and time served when they retire.

The deficit means that, at January 31st, the union could not meet current and future demands on its pension fund if it were closed at that point.

The note to Siptu's 2005 accounts states that the last full valuation of the pension fund was carried out in January 2004, when it was found to have a shortfall of €39 million.

Earlier this week, Siptu issued a statement saying it would not apply Financial Reporting Standard 17 (FRS17) to its accounts. This would have required it to detail its pension liability on its balance sheet, with the result that it would have shown that the union's liabilities exceeded assets by €2.6 million.

Excluding the €31 million pension shortfall, Siptu's net assets on December 31st, 2005, were €28.4 million.

Siptu general secretary, Joe O'Flynn said this week that, if the union had applied FRS 17, it would have significantly reduced net assets. He added that the union's 2005 revenue, €36.9 million, was a good financial performance.

In the note to its accounts, Siptu says that its position is that FRS 17's provisions are not in the best interests of members of defined benefit schemes, and are contrary to its policy of seeking that employers provide defined benefit schemes for workers.

Defined benefit schemes are more expensive than defined contribution pensions, where returns made on the cash invested in the fund determine the ultimate payout.

Siptu says that it has agreed a funding plan with the State Pensions Board .