The Illinois tollway's $500 million bond sale this month is the first of two expected this year to help fund a $12 billion construction program.
The tollway sold $500 million in bonds May 7 but ultimately ended up receiving $546 million from investors with a 4.3 percent interest rate, officials said Wednesday.
Principal and interest payments for the loan over 25 years will total $1.045 billion, assuming the agency doesn't refinance or pay off the debt before 2039.
The interest rate is lower than tollway estimates of around 6 percent back in summer 2011 when Move Illinois was approved.
"The market viewed the tollway bonds favorably," Finance Chief Mike Colsch said at a committee meeting.
Tollway officials intend to sell an additional $400 million in bonds for Move Illinois in 2014 plus $1.7 billion in 2015 and 2016.
About $5 billion of the road building program will be generated from loans while the remainder will come from toll revenues on a "pay-as-you-go" basis.
The construction is being financed with a toll increase that went into effect in January 2012.
Move Illinois projects include widening the Jane Addams Tollway (I-90), extending the Elgin-O'Hare Expressway and building an interchange at the Tri-State Tollway and I-57.
"Waiting to build these projects would cost more because of construction inflation," Colsch said in explaining the rationale for borrowing.