Iceland's central bank cut all its rates by 0.75 percentage points on Wednesday, slashing its benchmark interest rate to 5.5 percent. The bank also lowered its other rates by 0.75 points -- cutting its deposit rate to 4.0 percent, its maximum bid rate for 28-day certificates of deposit to 5.25 percent and its overnight lending rate to 7.0 percent, it said in a statement. As is its habit, the Sedlabanki gave no immediate reason for its decision but said it would provide more information later in the day. Since Iceland's massive financial and economic crisis in late 2008, when the main interest rate soared as high as 18 percent, the central bank has progressively reduced borrowing costs in an attempt to get the country's economy moving again. The Sedlabanki last lowered its main rate on September 22, also then by 0.75 points, pointing out that inflation, which at the height of the crisis passed 18 percent, was slowing and the Icelandic krona was appreciating. 