We have about 4 different methods of APY calculation for checking accounts. 365/365, 366/366...

If we choose to make them all 365/365, do we have to notify the customers we change? Does it have to be separate mailing or can we add it to the monthly statement as a message?

You are using different methods for CONSUMER accounts?

Apparently. Someone from another dep't asked me about this earlier. Still new here, and I don't have my boss to lean on today. ;-)

Reg DD: Appendix A to Part 230--Annual Percentage Yield Calculation

The annual percentage yield measures the total amount of interest paid on an account based on the interest rate and the frequency of compounding. The annual percentage yield is expressed as an annualized rate, based on a 365-day year. Part I of this appendix discusses the annual percentage yield calculations for account disclosures and advertisements, while Part II discusses annual percentage yield earned calculations for periodic statements.


The annual percentage yield reflects only interest and does not include the value of any bonus (or other consideration worth $10 or less) that may be provided to the consumer to open, maintain, increase or renew an account. Interest or other earnings are not to be included in the annual percentage yield if such amounts are determined by circumstances that may or may not occur in the future.

Institutions may calculate the annual percentage yield based on a 365–day or a 366–day year in a leap year.