The Chief Executive of the National Treasury Management Agency John Corrigan has described the sale of €5 billion worth of ten-year bonds as "particularly significant".
In an interview with RTÉ News, Mr Corrigan said Ireland "needed to get a ten year away" as those bonds are considered a flagship product in sovereign debt markets.
The yield on the new ten-year bond is 4.15%, which Mr Corrigan described as a "very low yield".
He said the last time Ireland issued a ten year bond - in January 2010 - it was sold with a 5% yield, and the lowest it ever traded was 4.4%.
Mr Corrigan said the issue was well supported, with a good spread of investors.
18% came from Ireland, 25% from the UK, 12% from the Nordic region, 33% rest of Europe and around 7% from the USA and rest of the world.
Mr Corrigan said about 60% of the debt was bought by real money investors, such as pension funds and insurance companies.
He said there was little interest from Asian investors, "reflecting Moody's rating, which continues to disappoint".
Moody's Investor Services is the only major ratings agency which rates Irish sovereign debt at below investment grade.
Mr Corrigan said the agency had expected to raise about €3 billion from the issue but, with €12 billion worth of bids, saw that it was possible to issue €5 billion at 4.15% and decided to go for it.
A ten-year bond is seen in the sovereign debt market as the benchmark.
Bonds with long maturities - ten years and longer - are attractive to pension funds and insurance companies, who tend to leave their money in the bonds longer, providing governments with a stable source of financing.
Shorter maturity bonds tend to be bought by bank treasury departments, and are subject to more volatile trading.
This morning’s ten-year bond issue "ticked all the boxes" for the NTMA, because it had good demand from real money investors, a good geographic and institutional spread, and a low interest rate.
This bond, and the five-year bond issued in January, brings the total raised by the NTMA this year to €7.5 billion, out of a fundraising target of €10 billion for the year.
Mr Corrigan said the NTMA may not need to raise much more during the remainder of the year:
“With today’s money, the 2017 bonds, the sale of Bank of Ireland cocos (contingent convertible debt, which raised €1.1 billion) and the sale of Irish Life (which brought in €1.3 billion), we are now very nearly fully funded,” he said.
“We will see how this issue trades, and see how the market settles down - €5 billion is a big issue. We may do some small trades later in the year, but we have to see how the market settles down first".
Ireland already is on course to get off support from the EU and IMF after raising over a quarter of its long-term funding target for this year in January.
Its steady market return has been helped by a sharp fall in Irish bond yields over the past 18 months.
Irish debt now trades below the equivalent levels of Spanish and Italian government bonds, two fellow euro zone strugglers which have avoided sovereign bailouts.
Yields on Ireland's current benchmark 2020 bond fell last week on a pledge by European Union finance ministers to agree to look at how to extend the maturity of emergency loans Ireland and Portugal have received under their bailouts.
In July 2011, the yield on the same bond had stood at more than 15%.
Finance Minister Michael Noonan has hailed today's NTMA bond auction as ''extraordinary''.
The Minister said the country is now in a very strong funding position and he congratulated the NTMA on the ''very effective'' result.