The interest rate used to be 17 percent, but officials said they did not sell at that rate.
One month ago, the Oil Ministry induced the Central Bank to raise the rate to 20 percent. The Oil Ministry said bonds at that rate sold like hotcakes and that the ministry actually issued more bonds than planned to take advantage of their popularity.
Central Bank Governor Mahmud Bahmani did not explain why he would be thinking of raising the bond payment rate another two percentage points if the bonds were selling easily at 20 percent.
The Oil Ministry has been issuing bonds in recent months to try to raise capital for development of the South Pars gasfield, which has ceased to draw foreign investment funds.
Musa Souri, managing director of South Pars Oil & Gas Co., suggested in January that it might be reasonable to raise the interest rate on bonds to 35 percent.
Because the Islamic Republic operates an Islamic banking system, the bond payments are officially not called interest but profits, although the rate of payment is set before the sale and before any profits can be calculated.