As long as you conduct your research to make your case and speak kindly, the expression “it never hurts to ask,” may actually benefit you when it comes to shopping around for a high yield CD investment. If you are a longtime customer of Bank A but notice that Bank B is advertising a better interest generating CD, feel free to ask your bank of choice if they can do anything better. The worse case scenario, they may say no and in the best case scenario you get a little more bang for your buck.
Typically the length of the investment and the current market interest rates generates the rate of return on CDs. If you are willing to invest your money for the longest period of time, you should normally get the best interest rate your bank has to offer. In the past, the CD interest rate was set in stone by the financial institution corporate offices. However, recently the trend has switched as big branch banks are giving their local branch managers a small degree of flexibility for the sake of retaining customers.
Whether or not you should settle for advertised CD rates really depends on you. If it is your bank that is advertising the best CD rate in town, you may be in a more limited position. However, the local branch manager may want to throw you a bone if you have had a long relationship with the bank or if you hold a substantial amount of products (investments, mortgage, personal loans, etc.) with them.
Ultimately the maximum amount a bank can raise a CD rate is between .25% and .50% of a percentage point. They cannot, and will not, increase the advertised CD rate so much that they reduce their profit margin too much. But why not give it a shot anyway, good luck!