The St. Tammany Parish Council unanimously accepted a low bid Thursday night by New York-based Merrill Lynch and Co. to finance construction of a 15,000-square-foot library in Madisonville.

Merrill Lynch, the lowest bidder out of four companies, offered a 4.06 interest rate to retire the $5 million debt borrowed for the project, bonding attorney Grant Schlueter told council officials at their monthly meeting.

“This is an extremely low interest rate,” he said. “Hard to beat.” The bid acceptance paves the way for construction of the new library expected to take up a third of the six-acre tract of land near the Maritime Museum in Madisonville. No timelines for completion have been set.

The low interest rate comes on the heels of an upgraded bond rating for St. Tammany Parish government by Standard and Poor’s, one of the nation’s top three bond rating companies.

The upgrade from AA- to AA places St. Tammany on par with Jefferson Parish, the only other governmental agency in the state with an AA rating. That rating is also “significantly higher than the state itself,” Schlueter said.

Similar to a credit rating, a bond rating reduces interest rates for long-term debts, meaning a roughly $50,000 savings for construction of the library, said Donald Westmoreland, finance director for the St. Tammany library system.

Preliminary plans call for a raised library with parking access underneath, Morgan said. Additional parking will be accessed at the Maritime Museum.

Renowned Dallas-based architect Denelle Wrightson has emerged as the Library Board’s design frontrunner. Wrightson is the designer of more than 100 projects nationwide and has designed libraries in Baton Rouge, Lafayette, Shreveport and other areas, Westmoreland said.