The World Bank’s International Development Association (IDA) launched the world’s first poverty bond this week, a debt offering representatives say is designed to lift up the poor, and global investors literally couldn’t get enough.

While IDA, which has never before raised money through a bond, issued just $1.5 billion in debt, international investors pledged $4.6 billion in offers – making the bond more than three times oversubscribed, a World Bank spokesman told Yahoo Finance.

“Yesterday we launched the first IDA bond. We went to market to raise money for the poor,” said World Bank CEO Kristalina Georgieva. “This is something that just five years ago people would say cannot be done.”

World Bank officials said the decision to issue the bond was based on a “transformation” in the market’s approach to bond buying.

“We are facing urgent and unparalleled development challenges,” George Richardson, director of capital markets for the World Bank Treasury told Yahoo Finance by email. “By making use of its strong financial position to tap capital markets and complement donor funding, IDA can to significantly scale up its support toward achieving the sustainable development goals, while offering donors value for their contributions.”

The International Development Association (IDA) is an arm of the World Bank that provides loans, and sometimes grants, to 75 of the world’s poorest countries. The association is overseen by 173 shareholder nations, with major shareholders including the U.S., Japan, United Kingdom, Germany and France. IDA says its mission is to fund programs that “boost economic growth, reduce inequalities, and improve people’s living conditions.”

The 5-year bond issued Tuesday is rated AAA and priced about 20 basis points above the 5-year U.S. government Treasury note. The IDA reported that it had $158 billion in equity — more than all the other multilateral banks combined.

When a bond is oversubscribed it means that there is strong demand for that particular issue. As many U.S. bonds have not performed well so far this year, investors have been hunting for bonds that are highly unlikely to default and pay them a higher coupon, or interest payment, than U.S. Treasuries.

In a statement that accompanied the announced bond sale, World Bank Group President Jim Yong Kim said that the issuance would allow the organization to “tap into the power of capital markets to tackle some of the world’s biggest challenges” and help millions of people to lift themselves out of poverty.

“We are an institution that has a track record to make the impossible real and we pledge to do it this time around,” Georgieva said.