The backing of AAA rated Islamic Development Bank is a boon to the debut sukuk Tunisia plans by July. The North African nation is planning to sell more than $100 million of Shariah-compliant bonds, Finance Minister Hakim Ben Hammouda said. That will help keep borrowing costs lower than they would be otherwise, said Mourad El Hattab at STB Bank. The guarantor will help keep the interest within the current range, El Hattab added. The IDB has provided Tunisia $3.6 billion in support. The yield on Tunisia’s 400 million-euro ($557 million) bonds maturing in 2020 fell three basis points to 4.42 percent at 11.59: a.m. on May 8 in Dubai, compared with a high for the year of 5.7 percent on Jan. 6.