Gap widens between intro and base rates 11 September 2012 4:53PM John Kavanagh Consumer lending, The gap between introductory rates and base rates on high-yield savings accounts is widening, leaving consumers exposed to sub-optimal rates if they do not review their accounts at the end of the introductory period.Financial research group Canstar said that rates can fall by as much as 185 basis points at the end of an introductory or promotional period.The average base rate is currently 3.7 per cent, while the average introductory rate is 126 basis points higher. Canstar financial analyst Adam Beu said in a statement: "We are seeing a steady upward trend in the margin between promotional and base rates, which is a way for banks to maintain an attractive headline rate while paying a lower ongoing rate."