Almost half of the National Pensions Reserve Fund (NPRF) - some €2.9 billion (£2.3 billion) - has been invested in almost 900 euro-zone and North American stocks since the beginning of the year, while a further €700 million has been invested in euro-zone bonds, the National Treasury Management Agency (NTMA) has disclosed.

This means that about 48 per cent of the current value of the fund - established to part-fund public service and social welfare old age pensions from 2025 onwards - has now been invested. The balance will be invested on a phased basis over the next few months after the remaining fund managers have been appointed.

The passively-managed equities element of the fund has now largely been invested, with Barclays Global Investors appointed to manage €1.8 billion of eurozone and North American equities while a Bank of Ireland Asset Management/State Street joint venture has won the mandate to manage €1.1 billion of euro-zone equities.

NTMA director Mr Ronan O'Connor said the €2.9 billion invested in equities since the start of the year went into 580 euro-zone stocks and about 300 North American stocks. As these passive investments were based on established indices, he said it was reasonable to assume that most major international household name stocks were involved in the fund's initial foray into equity markets. There is no compulsion on the euro-zone equity fund managers to invest in Irish stocks other than to reflect the Irish market's 1 per cent weighting within the euro zone.

The investment mandates that remain to be allocated include:

three pan-European funds each worth an initial €690 million;

one American equity enhanced index portfolio worth €400 million;

one American equity active growth fund worth €340 million;

one American active value portfolio worth €340 million;

one or possibly two Japanese active funds worth a total of €340 million;

one Pacific Basin (excluding Japan) fund worth €100 million;

two global equity funds worth €400 million;

one euro-zone long bond active fund worth €400 million.

Overall, the fund will be split 40 per cent euro-zone equities, 40 per cent non-euro-zone equities and 20 per cent euro-zone bonds (excluding Irish government bonds). The 80 per cent equity allocation will be roughly split 50-50 between active and passively managed funds.

NTMA director Mr John Corrigan said the fund managers would be paid on a fee basis, without any performance-related element. He emphasised that any non-performing fund manager could be removed from the fund "at a moment's notice".

And while the vast bulk of the fund's assets would be invested in public listed equities and bonds, NTMA chief executive Dr Michael Somers said some of the funds could be invested in national infrastructural projects, but only if these projects had the capacity to generate an "equity rate of return".

Mr O'Connor said the agency had exploratory discussions with the National Roads Authority on how the fund might become involved in financing major road and bridge projects. "Those talks are very much in their infancy.

"I personally would much prefer to put this money into Ireland but only if I thought we could get an equity rate of return," Dr Somers said. He said the fund would not be a cheap source of cash and that any investment in domestic infrastructure would be on a strictly equity basis. "In a PPP, we would be in the private part of the PPP," he said. But realistically, said Dr Somers, the vast bulk of the fund would be invested in equities and bonds. When funds are drawn down from the NPRF from 2025 onwards, the fund is expected to cover about 30 per cent of the State pension bill.